CompTIA Security+ (SY0-701) · glossary

Security+ glossary

803 terms you need for CompTIA Security+ (SY0-701), in plain words. Each one links to the lesson that teaches it. The acronym list is further down.

#A B C D E F G H I J K L M N O P Q R S T U V W Y Z Acronyms

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802.1X: 802.1X is port-based network access control: nothing but authentication traffic passes a switch port or Wi-Fi connection until the device authenticates. Lesson: Port security: 802.1X and EAP
A
AAA server: An AAA server (often reached through RADIUS or TACACS+) handles all three for VPNs, Wi-Fi and network devices. Lesson: The AAA framework
AAA/RADIUS: AAA/RADIUS: WPA2/WPA3-Enterprise sends each user's login through 802.1X to a RADIUS server for authentication, authorization and accounting. Lesson: Wireless security settings
Accept: Accept: knowingly live with it. Lesson: Risk management strategies
Acceptable use policy (AUP): Acceptable use policy (AUP): what users may and may not do with company systems. Lesson: Policies
Access badge: An access badge (often RFID or NFC, with a photo) identifies the holder and logs entry. Lesson: Eyes and IDs: video, guards, badges, lighting
Access control: Access control limits who and what reaches a resource: access control lists (ACLs) on routers, firewalls and files, and permissions (read, write, execute) on data. Lesson: Segmentation, access control, allow lists, isolation
Access control lists (ACLs): Access control limits who and what reaches a resource: access control lists (ACLs) on routers, firewalls and files, and permissions (read, write, execute) on data. Lesson: Segmentation, access control, allow lists, isolation
Access control vestibule: An access control vestibule (formerly called a mantrap) is a small room with two doors: usually only one may be open at a time, so one person at a time can be checked and tailgating is stopped. Lesson: Barriers: bollards, fencing, vestibules
Access lists: Firewall rules and access lists (ACLs) are read top-down; the first match wins, with an implicit deny at the end. Lesson: Firewalls: rules, ACLs, ports, screened subnets
Account lockout: Account lockout: many accounts (or a key one) suddenly locked from failed logins points to brute force or spraying, or an attacker locking users out on purpose. Lesson: Account clues
Accounting: Accounting records what it actually did: login time, resources used, data sent and received, logout time. Lesson: The AAA framework
Acquisition: Acquisition: collecting evidence (disk images, memory dumps), most volatile first: CPU cache and memory before disk. Lesson: Digital forensics
Acquisition/procurement process: Acquisition/procurement process: buy only from approved vendors, with security requirements in the purchase (supported OS, patch commitments, no default passwords). Lesson: Acquisition and assignment
Active: An active device can act on traffic (block, drop, reset). Lesson: Device attributes: active/passive, inline/tap
Ad hoc: Risk assessments can be ad hoc (for a specific event, like a new vendor), recurring (on a schedule, such as yearly), one-time (for a single project) or continuous (ongoing, automated monitoring of risk). Lesson: Identification and assessment types
Adaptive identity: Adaptive identity judges a login by its context, not just the password: device health, location, time, IP reputation, the user's role. Lesson: Control plane ideas
Advanced persistent threats (APTs): A nation-state actor works for a government: the most resources and the highest sophistication, patient long-term campaigns called advanced persistent threats (APTs), motives like espionage, data exfiltration,… Lesson: Nation-state and organized crime
AES: AES is the standard algorithm. Lesson: Symmetric encryption
Age: Age: minimum password age stops users from cycling through changes to reuse an old favorite. Lesson: Password concepts
Agent-based: Agent-based: software on each device filters wherever it goes, even at home. Lesson: Web filtering
Agentic: Automation (4.6) adds AI: agentic AI acts on its own, a chatbot answers questions, predictive analysis forecasts, and AI-augmented baselines learn what normal looks like. Lesson: Identity, automation and AI in operations
Agentless: Agentless software runs without an install, for example run on demand from a server or a web app; there is no footprint on devices, but a flaw on the central server affects every user at once. Lesson: Vulnerable software: client-based vs. agentless
Agents/agentless: Agents/agentless: an agent is software installed on the host (deep visibility, must be maintained); agentless collects remotely (nothing to install, less detail). Lesson: Monitoring tools, part 1
AH: IPSec works at layer 3: AH gives integrity and authentication only, ESP adds encryption. Lesson: VPN, remote access and tunneling
AI acceptable use policy: AI acceptable use policy, approved enterprise AI tools and DLP to stop data leakage. Lesson: Defenses
AI-assisted malware: AI also speeds up automated vulnerability discovery and AI-assisted malware development. Lesson: AI as the attacker's tool
AI-augmented baselines: Automation (4.6) adds AI: agentic AI acts on its own, a chatbot answers questions, predictive analysis forecasts, and AI-augmented baselines learn what normal looks like. Lesson: Identity, automation and AI in operations
AI-generated phishing: AI-generated phishing writes fluent, personalized lures, so spelling mistakes are no longer a reliable sign. Lesson: AI as the attacker's tool
Air gap: They can also cross an air gap into networks that aren't online, and carry data out. Lesson: Voice call and removable device
Air-gapped: The extreme is air-gapped: no network connection to anything else, so data moves only by removable media (which becomes the main risk). Lesson: Physical isolation, logical segmentation, SDN
Alert tuning: Alert tuning: adjust rules to cut false positives without creating false negatives. Lesson: Monitoring activities
Alerting: Alerting: rules or analytics raise an alert when something matches. Lesson: Monitoring activities
Algorithm: The algorithm is the math (AES, RSA, ECC); the key is the secret input. Lesson: Algorithms and key length
Allow list: A new app version may be blocked by the allow list (or flagged by a deny list) until the list is updated, so update the lists as part of the change. Lesson: Allow/deny lists and restricted activities
Amplified: Amplified: the attacker picks requests whose replies are far larger than the request (DNS, NTP, memcached), multiplying the flood. Lesson: DDoS: reflected and amplified
Analysis: Analysis: confirming it is a real incident, its scope and severity. Lesson: The incident response process
Annualized loss expectancy (ALE): Annualized loss expectancy (ALE) = SLE x ARO. Lesson: The money formulas
Annualized rate of occurrence (ARO): Annualized rate of occurrence (ARO): how many times a year it is expected (0.1 = once in ten years). Lesson: The money formulas
Anti-bribery: opt-out, data correction, processing restrictions and prevention, AML/CTF and anti-bribery** training. Lesson: Program management additions
Antivirus: Antivirus: detects and removes known malware on endpoints. Lesson: Monitoring tools, part 2
Application allow list: An application allow list lets only approved programs run; everything else is blocked. Lesson: Segmentation, access control, allow lists, isolation
Application logs: Application logs: what the app did (logins to the shop, errors, transactions). Lesson: Log data
Application restart: Many changes need a service restart (for example restarting the web service so a new config loads) or an application restart. Lesson: Downtime and restarts
Applications: Three layers of computing resources: Systems (servers, workstations: CPU, logins, processes), Applications (errors, failed logins, unusual transactions in the shop app) and Infrastructure (network devices, firewalls,… Lesson: What we monitor
Approval process: The approval process sends a change request through review (often the CAB) before any work starts; emergency changes get a faster path, not no path. Lesson: Approval, ownership, stakeholders
Archiving: Archiving: keep older logs in cheaper storage for investigations and compliance. Lesson: Monitoring activities
ARP poisoning: An on-path attack (formerly man-in-the-middle) puts the attacker between two parties to read or change traffic, for example with ARP poisoning on a LAN. Lesson: On-path, credential replay, malicious code
Assessment: An assessment evaluates controls against a standard or framework and reports gaps. Lesson: External audits and assessments
Assignment/accounting: Assignment/accounting: every asset gets ownership: an owner, a person accountable for it, and a classification (how sensitive or critical it is), which decides how it must be protected. Lesson: Acquisition and assignment
Asymmetric encryption: Asymmetric encryption uses a mathematically linked key pair. Lesson: Asymmetric encryption
At rest: At rest: stored on disks, databases, backups (protect with full-disk or database encryption and permissions). Lesson: Data states
Attack surface: The attack surface is the total of all the places that could be attacked: every app, port, device, account and person. Lesson: Vectors vs. attack surface
Attestation: Attestation means proving a claim. Lesson: Attestation
Attestation and acknowledgement: Attestation and acknowledgement: people formally confirm they read and accept policies, and leaders sign statements that controls are in place. Lesson: Compliance monitoring
Attribute-based: Attribute-based (ABAC): decisions combine many attributes: user, resource, device, location, time. Lesson: Access control models
Attributes: CompTIA compares actors on three attributes. Lesson: Attributes of actors
Audit: Validation of remediation: rescanning to confirm the finding is gone, an audit to check the change was made correctly, and verification (testing directly, for example confirming the patched version is running). Lesson: Validation and reporting
Audit charter: Audits (5.5): MITRE ATT&CK (tactics and techniques), Cyber Kill Chain (seven phases), Diamond Model (adversary, capability, infrastructure, victim), audit charter, sampling and assertions. Lesson: Program management additions
Audit committee: The audit committee (usually a board committee) oversees internal and external audits and makes sure findings are fixed. Lesson: Internal audits and assessments
Authenticating people: Authenticating people uses factors such as something you know, have or are, ideally MFA. Lesson: Authenticating people and authenticating systems
Authenticating systems: Authenticating systems proves a device is one of yours, even with no person at the keyboard. Lesson: Authenticating people and authenticating systems
Authentication: Authentication proves it (password, MFA, certificate). Lesson: The AAA framework
Authentication protocols: Authentication protocols: EAP methods such as EAP-TLS (certificates), PEAP and EAP-TTLS. Lesson: Wireless security settings
Authentication server: Three roles: the supplicant (the client), the authenticator (the switch or access point) and the authentication server (usually RADIUS). Lesson: Port security: 802.1X and EAP
Authenticator: Three roles: the supplicant (the client), the authenticator (the switch or access point) and the authentication server (usually RADIUS). Lesson: Port security: 802.1X and EAP
Authorization: Authorization decides what that identity may do. Lesson: The AAA framework
Authorization models: Authorization models put an abstraction between users and resources: users go into a role or group (Shipping Clerks), and the role gets the rights. Lesson: Authorization models
Automated reports: Automated reports from tools summarize activity on a schedule. Lesson: Other data sources
Automated vulnerability discovery: AI also speeds up automated vulnerability discovery and AI-assisted malware development. Lesson: AI as the attacker's tool
Automation: Automation tracks compliance continuously with tools instead of yearly spreadsheets. Lesson: Compliance monitoring
Availability: Availability makes sure systems and data are there when authorized people need them (redundancy, fault tolerance, patching, DDoS protection). Lesson: Confidentiality, integrity, availability
Avoid: Avoid: stop the activity that creates the risk. Lesson: Risk management strategies
B
Backout plan: A backout plan is the tested way to undo the change and return to the last good state if it fails, for example restoring a snapshot or the previous config. Lesson: Backout plan, maintenance window, SOP
Backup codes: Identity (4.5) adds identity proofing before accounts are issued, emergency access (break-glass) accounts, backup codes, passkeys (phishing-resistant FIDO2 keys), time-based access and compromised credential monitoring. Lesson: Identity, automation and AI in operations
Baseline: Steps: pick the target, document the current state (a baseline) for people, processes and technology, compare, list the gaps, then build a plan with costs and timelines to close them. Lesson: Where are we vs. where should we be?
Bcrypt: Examples: PBKDF2 and bcrypt (scrypt and Argon2 also add memory cost). Lesson: Key stretching
Benchmarks: Benchmarks (such as CIS Benchmarks): published secure-configuration guides that SCAP tools can test against. Lesson: Monitoring tools, part 1
BIMI: BIMI: shows a brand logo in inboxes, only for domains enforcing DMARC. Lesson: Architecture and operations tools
Birthday: A birthday attack uses the birthday paradox: finding any two inputs with matching hashes takes far fewer tries than matching one specific hash. Lesson: Downgrade, collision, birthday
Blackmail: Blackmail: threatening to leak or harm unless paid. Lesson: Why they attack
Bloatware: Bloatware is unnecessary software preinstalled by the maker; it wastes resources and widens the attack surface with apps nobody patches. Lesson: Spyware, keylogger, bloatware
Block rules: Block rules: explicit allow/deny lists. Lesson: Web filtering
Blockchain: A blockchain is a distributed ledger of transactions grouped into blocks; each block contains the hash of the previous one, so changing any old block breaks every hash after it. Lesson: Blockchain and the open public ledger
Blocked content: Blocked content: security tools blocking attempts to reach known bad sites, or malware blocking access to security updates and security sites. Lesson: System and content clues
Bluetooth: Unsecure networks: wireless (open Wi-Fi, old WEP/WPA, rogue access points), wired (open network jacks with no 802.1X or port security, so anyone can plug in), and Bluetooth (devices left discoverable, flaws in… Lesson: Unsupported systems and unsecure networks
Boards: Boards (board of directors) set direction and are ultimately accountable. Lesson: Types of governance structures
Bollards: Bollards are short posts that stop vehicles from ramming a doorway while letting people walk through. Lesson: Barriers: bollards, fencing, vestibules
BPA: BPA (business partners agreement): terms for a partnership: ownership stake, profit sharing, decisions. Lesson: Agreement types
Brand impersonation: Brand impersonation copies a known brand's logos and style in emails or sites to borrow its trust. Lesson: Watering hole, brand impersonation, typosquatting
Browser-based: Browser-based: extensions, JavaScript, password managers, cookies and session tokens. Lesson: Vectors and attack surfaces added in V8
Brute force: A physical brute force attack forces entry: breaking a window, prying a door, ramming a gate with a vehicle (which bollards stop). Lesson: Brute force, RFID cloning, environmental
Buffer overflow: A buffer overflow happens when a program writes more data into a memory buffer than it was built to hold, overwriting nearby memory; a crafted overflow can crash the app or let the attacker run their own code. Lesson: Memory injection and buffer overflow
Bug bounty program: A bug bounty program adds rewards for valid reports. Lesson: Pen tests, disclosure programs and audits
Business continuity: Business continuity and disaster recovery policies: keeping the business running and restoring IT after a disaster. Lesson: Policies
Business email compromise (BEC): Business email compromise (BEC) uses a real compromised business email account or a convincing fake one, often an executive's or a vendor's, to get staff to wire money, change bank details or send sensitive data. Lesson: Impersonation, pretexting, BEC
Business impact analysis: A business impact analysis (BIA) measures what downtime costs and sets targets: Lesson: Risk reporting and business impact analysis
BYOD: BYOD (bring your own device): employee owns it; hardest to control, privacy concerns. Lesson: Mobile solutions
C
Campaigns: Three parts: campaigns send realistic simulated phishing emails to staff on a schedule and measure who clicks and who reports. Lesson: Phishing
Canary account: Canary account and honeynet: decoys; any use is a high-confidence alert. Lesson: Architecture and operations tools
Capacity planning: Capacity planning makes sure there is enough of three things when demand jumps or a site fails: people (enough trained staff, cross-training), technology (servers, licenses, app capacity) and infrastructure (power,… Lesson: Continuity of operations and capacity planning
CAPTCHA: Image-based: QR codes, embedded content and fake CAPTCHA pages. Lesson: Vectors and attack surfaces added in V8
Captive portals: Rate limiting, captive portals, endpoint posture checks and secrets scanning of repositories. Lesson: Architecture and operations tools
Category: The category says how it is carried out: technical, managerial, operational or physical. Lesson: What a security control is
Cellular: Connection methods: Cellular (carrier network, bypasses company Wi-Fi controls), Wi-Fi (watch for rogue APs and evil twins), Bluetooth (turn off discoverable mode, pair only known devices). Lesson: Mobile solutions
Centralized: Centralized designs manage everything from one place (one directory, one log server): consistent policy and easy visibility, but a single point of failure and a juicy target. Lesson: On-premises, centralized or decentralized
Centralized proxy: Centralized proxy: all web traffic passes through one proxy at the company edge. Lesson: Web filtering
Certificate authority (CA): A digital certificate binds a public key to an identity and is signed by a certificate authority (CA). Lesson: CAs, third-party and self-signed
Certificate revocation list (CRL): A certificate revocation list (CRL) is a list of revoked serial numbers that the CA publishes; clients download the whole list periodically. Lesson: Revocation: CRL and OCSP
Certification: Certification: a documented certificate of sanitization or destruction, usually from the disposal vendor, as proof. Lesson: Disposal and decommissioning
Chain: Trust flows down a chain: root CA signs an intermediate CA, which signs the server certificate. Lesson: Root of trust and the chain
Chain of custody: Chain of custody: a record of every person who handled the evidence, when and why. Lesson: Digital forensics
Change advisory board (CAB): Most organizations run changes through a change advisory board (CAB). Lesson: Why change management is security
Change management: Change management is the formal process for proposing, reviewing, approving, testing, scheduling and documenting changes to systems. Lesson: Why change management is security
Chatbot: Automation (4.6) adds AI: agentic AI acts on its own, a chatbot answers questions, predictive analysis forecasts, and AI-augmented baselines learn what normal looks like. Lesson: Identity, automation and AI in operations
CIA triad: The CIA triad is the core goal of security. Lesson: Confidentiality, integrity, availability
Classification: Assignment/accounting: every asset gets ownership: an owner, a person accountable for it, and a classification (how sensitive or critical it is), which decides how it must be protected. Lesson: Acquisition and assignment
Client-based: Client-based software is installed on each device (an agent or app), so a flaw exists on every device it's on and each must be patched. Lesson: Vulnerable software: client-based vs. agentless
Cloud infrastructure: Cloud infrastructure: least-privilege IAM, no public storage by default, logging on, secure templates. Lesson: Hardening targets
Cloud-specific: Cloud-specific vulnerabilities come with cloud services: publicly exposed storage buckets, weak identity and access settings, insecure APIs, unprotected management consoles, and confusion over the shared… Lesson: Cloud-specific and supply chain
Clustering: Clustering makes several servers work together as one system, aware of each other, often sharing storage, so one node takes over the service if another fails (active/passive or active/active). Lesson: High availability: load balancing vs clustering
Code signing: Code signing: a digital signature proves who published the code and that it was not altered. Lesson: Application security
Cold site: Cold site: space, power and cooling only; you bring everything (cheapest, slowest). Lesson: Site considerations
Collaboration tools: Message-based: email, SMS, RCS, instant messaging and collaboration tools. Lesson: Vectors and attack surfaces added in V8
Collision: A collision is two different inputs that produce the same hash, which lets a forged file pass a hash check (MD5 and SHA-1 are vulnerable). Lesson: Downgrade, collision, birthday
Committees: Committees (such as a security steering committee) handle specific areas and report up. Lesson: Types of governance structures
Compensating control: A compensating control is an alternative used when the normal control is not possible or too costly: an old warehouse PC that can't be patched gets isolated on its own VLAN with extra monitoring. Lesson: Compensating and directive
Compensating controls: Compensating controls: other controls that reduce the risk when the fix is impossible (extra monitoring, a WAF rule). Lesson: Response and remediation
Compliance: Compliance audits check that internal rules and outside requirements are being followed. Lesson: Internal audits and assessments
Compliance reporting: Compliance reporting can be internal (to management and the board, tracking how well rules are followed) or external (to regulators, card brands, customers). Lesson: Compliance reporting and consequences
Compromised credential monitoring: Identity (4.5) adds identity proofing before accounts are issued, emergency access (break-glass) accounts, backup codes, passkeys (phishing-resistant FIDO2 keys), time-based access and compromised credential monitoring. Lesson: Identity, automation and AI in operations
Compute: Compute: processing capacity available. Lesson: Considerations: the trade-off checklist
Concurrent session usage: Concurrent session usage: one account logged in from two places at once when the user can only be in one. Lesson: Account clues
Confidential: Confidential: limited to approved people (contracts, pricing plans). Lesson: Data classifications
Confidentiality: Confidentiality keeps data secret from anyone not authorized (encryption, access controls, MFA). Lesson: Confidentiality, integrity, availability
Configuration enforcement: Configuration enforcement makes systems match an approved secure baseline and keeps them that way, for example Group Policy, MDM, or network access control that checks posture before a device connects. Lesson: Configuration enforcement and decommissioning
Conflict of interest: Conflict of interest: make sure no one choosing the vendor gains personally from the choice. Lesson: Vendor selection, questionnaires, monitoring, rules of engagement
Connectivity: Connectivity: decide how zones and sites link (VPN, leased line, SD-WAN) and secure each link. Lesson: Placement, zones, attack surface, connectivity
Consequences of non-compliance: Consequences of non-compliance: fines, sanctions (restrictions or penalties imposed by regulators or governments), reputational damage, loss of license (losing the right to operate or to process cards) and… Lesson: Compliance reporting and consequences
Conservative: It can be expansionary (willing to take more risk for growth), conservative (prefers low risk) or neutral (balanced). Lesson: Tolerance and appetite
Containerization: Containerization: containers package an app with its libraries and share the host OS kernel. Lesson: Virtualization and containerization
Containment: Containment: stopping the spread (isolate hosts, disable accounts). Lesson: The incident response process
Content categorization: Content categorization: blocks by category (gambling, malware). Lesson: Web filtering
Continuity of operations (COOP): Continuity of operations (COOP) is the plan to keep essential functions running during a disruption, even in a reduced or manual way (paper order forms when the POS is down). Lesson: Continuity of operations and capacity planning
Continuous: Risk assessments can be ad hoc (for a specific event, like a new vendor), recurring (on a schedule, such as yearly), one-time (for a single project) or continuous (ongoing, automated monitoring of risk). Lesson: Identification and assessment types
Contractual impacts: Consequences of non-compliance: fines, sanctions (restrictions or penalties imposed by regulators or governments), reputational damage, loss of license (losing the right to operate or to process cards) and… Lesson: Compliance reporting and consequences
Control plane: The architecture splits into two parts: the control plane (where policy is made and decisions are taken) and the data plane (where the traffic actually flows and the decision is enforced). Lesson: Never trust, always verify
Controller: The controller decides why and how personal data is processed; the processor processes it for the controller. Lesson: Privacy
Controllers: Controllers: decide why and how personal data is processed (the purposes and means). Lesson: Roles for systems and data
COPE: COPE (corporate-owned, personally enabled): company owns it, user may use it personally. Lesson: Mobile solutions
Corrective: Awareness (5.6): an LMS to deliver and track training, targeted and corrective training, personnel behavior risk scoring. Lesson: Program management additions
Corrective control: A corrective control reduces the damage and restores normal operation after an event: restoring from backup, antivirus removing malware, a patch that fixes the hole that was used. Lesson: Detective and corrective
Cost: Cost: purchase plus running costs. Lesson: Considerations: the trade-off checklist
Cover: Steganography hides data inside other data, the cover (cover text/image): a message inside the pixels of a photo, an audio file, a video, or packet fields. Lesson: Steganography
Credential replay: Credential replay captures login data (a password hash, a token) and reuses it to log in without knowing the password; pass the hash is an example. Lesson: On-path, credential replay, malicious code
Critical: Critical: data the business cannot run without; availability matters most. Lesson: Data classifications
Cross-site request forgery (CSRF): Forgery makes a server or browser send requests the user didn't intend: cross-site request forgery (CSRF) abuses a logged-in user's browser; server-side request forgery (SSRF) makes a server fetch internal resources. Lesson: Privilege escalation, forgery, directory traversal
Cross-site scripting (XSS): Cross-site scripting (XSS) gets a site to send attacker JavaScript to other users' browsers, where it runs as if the trusted site sent it (stealing session cookies, rewriting the page). Lesson: Cross-site scripting (XSS)
Cryptographic: Cryptographic vulnerabilities: weak or outdated algorithms (MD5, SHA-1, DES), short keys, poor key management (keys hard-coded in code, never rotated), bad random numbers or flawed implementations. Lesson: Cryptographic and misconfiguration
Cryptographic protocols: Cryptographic protocols: WPA2 uses CCMP with AES; WPA3 keeps AES and adds a 192-bit mode with GCMP-256. Lesson: Wireless security settings
CSPM: CSPM: continuous checks of cloud settings; IPAM: tracks IP space and finds hosts scans miss. Lesson: Architecture and operations tools
CSR generation: CSR generation: you create a key pair, then a certificate signing request with the public key and identity details (common name, SANs, organization) signed with your private key. Lesson: CSR generation and wildcards
Custodians/stewards: Custodians/stewards: handle data day to day; custodians apply the controls (backups, permissions), stewards keep data accurate, labeled and compliant. Lesson: Roles for systems and data
CVE: A CVE is a unique public ID for a known vulnerability (format CVE-year-number; the program is Common Vulnerabilities and Exposures, listed in the objectives as "Common Vulnerability Enumeration"). Lesson: CVE and CVSS
CVSS: CVSS (Common Vulnerability Scoring System) scores severity from 0.0 to 10.0. Lesson: CVE and CVSS
Cyber Kill Chain: Audits (5.5): MITRE ATT&CK (tactics and techniques), Cyber Kill Chain (seven phases), Diamond Model (adversary, capability, infrastructure, victim), audit charter, sampling and assertions. Lesson: Program management additions
CYOD: CYOD (choose your own device): user picks from an approved list; company owns and manages it. Lesson: Mobile solutions
D
Dark web: Dark web: monitoring criminal forums and markets for leaked company data or planned attacks. Lesson: Threat feeds
Dashboards: Dashboards give a live visual overview to spot spikes and trends. Lesson: Other data sources
Data correction: opt-out, data correction, processing restrictions and prevention, AML/CTF and anti-bribery** training. Lesson: Program management additions
Data exfiltration: Data exfiltration: stealing data to sell or use. Lesson: Why they attack
Data inventory: A data inventory lists what personal data you hold and where; retention keeps it only as long as needed. Lesson: Privacy
Data leakage: Data leakage: staff paste secrets or customer data into public AI tools that may keep it. Lesson: Poisoning, theft and leakage
Data masking: Data masking hides part or all of a value when it is shown or copied, such as showing a Social Security number as XXX-XX-6789, or swaps in fake data for testing, so people see only what they need. Lesson: Tokenization and data masking
Data plane: The architecture splits into two parts: the control plane (where policy is made and decisions are taken) and the data plane (where the traffic actually flows and the decision is enforced). Lesson: Never trust, always verify
Data poisoning: Data poisoning: tampering with training or feedback data so the model learns wrong or malicious behavior. Lesson: Poisoning, theft and leakage
Data retention: Data retention: keep data only as long as law and policy require, then dispose of it. Lesson: Disposal and decommissioning
Data sovereignty: Data sovereignty: data is subject to the laws of the country where it is stored, so where you put it matters. Lesson: Data sovereignty and geolocation
Data subject: The data subject is the person the data is about. Lesson: Privacy
Database: Database encryption protects a whole database (transparent data encryption). Lesson: Data at rest: from disk to record
Deauthentication: Wireless attacks include deauthentication floods that kick users off Wi-Fi (802.11w management frame protection helps), jamming of the radio frequencies, and evil twin or rogue access points that capture traffic. Lesson: DNS attacks and wireless attacks
Decentralized: Decentralized designs spread control across sites or owners (each store runs its own systems): more resilient to one failure, harder to keep consistent and to monitor. Lesson: On-premises, centralized or decentralized
Decommissioning: Decommissioning retires systems safely: remove them from the network and inventory, revoke their accounts and certificates, and wipe or destroy their storage so no data leaks. Lesson: Configuration enforcement and decommissioning
Deepfake: Objective 2.5 adds quishing (QR phishing), deepfake impersonation, skimming and forced entry, forgery attacks such as SSRF, and credential attacks like user enumeration and MFA bypass (push fatigue, stolen session… Lesson: New attacks and indicators of compromise
Deepfakes: Deepfakes clone voices and faces for fake calls from executives. Lesson: AI as the attacker's tool
Default credentials: Default credentials are the factory usernames and passwords (admin/admin) on routers, cameras, printers and IoT gear; attackers keep lists of them and scan for devices that still use them. Lesson: Open service ports and default credentials
Default password changes: CompTIA lists: encryption (full-disk, files), installation of endpoint protection (antivirus/EDR), a host-based firewall that filters traffic on the device itself, a host-based intrusion prevention system (HIPS) that… Lesson: Make each host harder to break
Defensive: Defensive: detecting and responding to the attack (blue team). Lesson: Pen test types
Deny list: A new app version may be blocked by the allow list (or flagged by a deny list) until the list is updated, so update the lists as part of the change. Lesson: Allow/deny lists and restricted activities
Dependencies: Dependencies are things that rely on each other: updating a database server may require the app servers to be updated first, or a service may not start until another one is running. Lesson: Legacy applications and dependencies
Deploy: Deploy it the same way everywhere with tools (Group Policy, MDM, configuration management, IaC templates). Lesson: Secure baselines: establish, deploy, maintain
Destruction: Destruction: physically ruin the media (shredding, pulverizing, incinerating; degaussing for magnetic media). Lesson: Disposal and decommissioning
Detection: Detection: noticing that something is wrong (alerts, user reports). Lesson: The incident response process
Detective control: A detective control identifies and records an event during or after it happens: an IDS alert, log review, a motion sensor, a camera recording. Lesson: Detective and corrective
Deterrent control: A deterrent control discourages an attacker from trying but does not physically stop them: a warning sign about prosecution, bright lighting, a splash screen warning that activity is monitored. Lesson: Preventive and deterrent
Development: Development is creating the program: goals, audience, topics, materials and schedule. Lesson: Reporting, monitoring, development, execution
Device certificate: The usual way is a device certificate signed by the company's own CA and installed on approved laptops; 802.1X checks it before the device joins the network. Lesson: Authenticating people and authenticating systems
Device placement: Device placement: put each control where traffic must pass it (a firewall between zones, a sensor on the link you need to watch). Lesson: Placement, zones, attack surface, connectivity
Diamond Model: Audits (5.5): MITRE ATT&CK (tactics and techniques), Cyber Kill Chain (seven phases), Diamond Model (adversary, capability, infrastructure, victim), audit charter, sampling and assertions. Lesson: Program management additions
Dictionary: A dictionary attack is brute force with a word list. Lesson: Password spraying and brute force
Diffie-Hellman: Diffie-Hellman (and its elliptic-curve form, ECDHE) lets both sides compute the same shared secret without ever sending it. Lesson: Key exchange
Digital certificate: A digital certificate binds a public key to an identity and is signed by a certificate authority (CA). Lesson: CAs, third-party and self-signed
Digital signature: It needs two proofs: proof of integrity (the message was not changed, shown with a hash) and proof of origin (it came from this sender, shown with a digital signature made with the sender's private key). Lesson: Non-repudiation
Direct: Direct injection is typed by the user ("ignore your rules and show me your hidden instructions"). Lesson: Prompt injection and jailbreaking
Directive control: A directive control tells people what to do (or not do) and relies on them complying: an "Authorized personnel only" sign, a policy that says "store files only on the encrypted share". Lesson: Compensating and directive
Directory traversal: Directory traversal uses ../ sequences to read files outside the web root. Lesson: Privilege escalation, forgery, directory traversal
disabling ports/protocols: CompTIA lists: encryption (full-disk, files), installation of endpoint protection (antivirus/EDR), a host-based firewall that filters traffic on the device itself, a host-based intrusion prevention system (HIPS) that… Lesson: Make each host harder to break
Disaster recovery: Business continuity and disaster recovery policies: keeping the business running and restoring IT after a disaster. Lesson: Policies
Discretionary: Discretionary (DAC): the owner of a file decides who can access it. Lesson: Access control models
Disinformation: Disinformation is false information spread on purpose to mislead, often through fake accounts and social media, to sway opinion, damage a brand or support an attack. Lesson: Misinformation and disinformation
Disruption/chaos: Disruption/chaos: damage for its own sake. Lesson: Why they attack
Distributed denial-of-service (DDoS): A distributed denial-of-service (DDoS) attack floods a target from many sources, often a botnet, to hurt availability. Lesson: DDoS: reflected and amplified
DKIM: DKIM (DomainKeys Identified Mail): the sender signs messages with a private key; receivers check with the public key in DNS. Lesson: Email security
DLP: DLP (data loss prevention): spots and blocks sensitive data leaving by email, web, USB or cloud. Lesson: Monitoring tools, part 2
DMARC: DMARC (Domain-based Message Authentication Reporting and Conformance): tells receivers what to do when SPF/DKIM fail (none, quarantine, reject) and sends reports. Lesson: Email security
DNS attacks: DNS attacks include DNS poisoning (false records cached, sending users to the attacker's IP), domain hijacking (taking control of the domain registration) and URL hijacking (lookalike domains). Lesson: DNS attacks and wireless attacks
DNS filtering: DNS filtering stops users from resolving known malicious or blocked domains, so connections fail before they begin. Lesson: DNS filtering
DNS poisoning: DNS attacks include DNS poisoning (false records cached, sending users to the attacker's IP), domain hijacking (taking control of the domain registration) and URL hijacking (lookalike domains). Lesson: DNS attacks and wireless attacks
Domain hijacking: DNS attacks include DNS poisoning (false records cached, sending users to the attacker's IP), domain hijacking (taking control of the domain registration) and URL hijacking (lookalike domains). Lesson: DNS attacks and wireless attacks
Downgrade: A downgrade attack forces two sides to use an older, weaker protocol or cipher (for example pushing a TLS 1.3 client back to an old, broken protocol version) so the attacker can break it. Lesson: Downgrade, collision, birthday
Downtime: Downtime is the time a service is unavailable during the change; plan it inside the maintenance window and tell stakeholders. Lesson: Downtime and restarts
Due diligence: Due diligence: investigate a vendor before choosing it (security, finances, reputation, legal history). Lesson: Vendor selection, questionnaires, monitoring, rules of engagement
Due diligence/care: Due diligence/care: due diligence is investigating and understanding your obligations and risks; due care is acting on them responsibly (doing the reasonable things a prudent organization would). Lesson: Compliance monitoring
Dynamic analysis: For applications: static analysis reviews source code without running it; dynamic analysis tests the running app (including fuzzing with unexpected input); package monitoring tracks the third-party libraries and… Lesson: Vulnerability scans and application testing
E
E-discovery: E-discovery: finding and handing over electronic information for legal proceedings. Lesson: Digital forensics
EAP: EAP (Extensible Authentication Protocol) is the framework that carries the login inside 802.1X: EAP-TLS uses certificates on both sides; PEAP and EAP-TTLS build a TLS tunnel first. Lesson: Port security: 802.1X and EAP
Ease of deployment: Ease of deployment: how fast can we roll it out? Lesson: Considerations: the trade-off checklist
Ease of recovery: Ease of recovery: how fast back after failure? Lesson: Considerations: the trade-off checklist
EDR/XDR: EDR/XDR: EDR records and responds to threats on endpoints; XDR extends that across endpoints, network, cloud and email. Lesson: Endpoint and data capabilities
efficiency/time saving: Why automate: efficiency/time saving; enforcing baselines and standard infrastructure configurations (no drift, no typos); scaling in a secure manner (100 servers built as safely as one); employee retention (fewer… Lesson: Benefits
Email: Message-based vectors: email (phishing links and attachments), SMS text messages and instant messaging (IM) in chat apps. Lesson: Message-based, image-based, file-based
Embedded systems: Embedded systems: a computer built into a device for one job. Lesson: IoT, ICS/SCADA, RTOS and embedded systems
Emergency access: Identity (4.5) adds identity proofing before accounts are issued, emergency access (break-glass) accounts, backup codes, passkeys (phishing-resistant FIDO2 keys), time-based access and compromised credential monitoring. Lesson: Identity, automation and AI in operations
Employee retention: Why automate: efficiency/time saving; enforcing baselines and standard infrastructure configurations (no drift, no typos); scaling in a secure manner (100 servers built as safely as one); employee retention (fewer… Lesson: Benefits
Encryption: Encryption protects data at rest and in transit so stolen data is unreadable. Lesson: Patching, encryption, monitoring, least privilege
End-of-life (EOL): End-of-life (EOL) means the maker has stopped selling it; patches may continue for a while, but once support ends too (end of service life) new flaws stay open. Lesson: Firmware, end-of-life, legacy
Endpoint logs: Endpoint logs: activity on the device (processes started, files, USB use), often from EDR. Lesson: Log data
Endpoint-based: Endpoint-based: trusted devices, built-in tools and living-off-the-land tools. Lesson: Vectors and attack surfaces added in V8
Enforcing baselines: Why automate: efficiency/time saving; enforcing baselines and standard infrastructure configurations (no drift, no typos); scaling in a secure manner (100 servers built as safely as one); employee retention (fewer… Lesson: Benefits
Enumeration: Enumeration is actively discovering and listing what is really out there (network scans, agent check-ins, cloud APIs) so unknown or rogue devices show up and can be compared against the inventory. Lesson: Monitoring and asset tracking
Environmental variables: Prioritize using: vulnerability classification (what kind of flaw and how severe), exposure factor (the percentage of the asset's value that would be lost if the flaw is exploited), environmental variables (is it… Lesson: Prioritize with context
EOI: RFI (what can vendors do?), RFP (detailed proposals), RFQ (prices for a defined order), EOI (who is interested?). Lesson: Program management additions
Ephemeral credentials: PAM tools control them: just-in-time permissions grant admin rights only when needed for a set period, then remove them; password vaulting stores privileged credentials in a vault where admins check them out (logged… Lesson: Privileged access management (PAM)
Eradication: Eradication: removing the cause (malware, attacker accounts, the exploited flaw). Lesson: The incident response process
Escalation: Ticket creation and escalation: open a ticket from an alert and escalate it if nobody acts in time. Lesson: Use cases of automation and scripting
ESP: IPSec works at layer 3: AH gives integrity and authentication only, ESP adds encryption. Lesson: VPN, remote access and tunneling
Espionage: Espionage: spying for a government or competitor. Lesson: Why they attack
Establish: Establish it from trusted guidance (CIS Benchmarks, vendor security guides) and test it. Lesson: Secure baselines: establish, deploy, maintain
Ethical: Ethical: hacking to improve security, such as authorized testers and bug-bounty researchers who disclose responsibly. Lesson: Why they attack
Evil twin: Wireless attacks include deauthentication floods that kick users off Wi-Fi (802.11w management frame protection helps), jamming of the radio frequencies, and evil twin or rogue access points that capture traffic. Lesson: DNS attacks and wireless attacks
Examinations: Examinations are formal reviews by an outside body (such as a regulator examining records). Lesson: External audits and assessments
Exception: Includes an exemption (formally released from a requirement) and an exception (approved, usually temporary deviation from a policy, with compensating controls). Lesson: Risk management strategies
Exceptions and exemptions: Exceptions and exemptions: formally approved and documented decisions not to fix (yet), with an owner and review date. Lesson: Response and remediation
Execution: Execution is running it: delivering training, sending campaigns, tracking completion and adjusting based on results. Lesson: Reporting, monitoring, development, execution
Exemption: Includes an exemption (formally released from a requirement) and an exception (approved, usually temporary deviation from a policy, with compensating controls). Lesson: Risk management strategies
Expansionary: It can be expansionary (willing to take more risk for growth), conservative (prefers low risk) or neutral (balanced). Lesson: Tolerance and appetite
Expiration: Expiration: forced change after a set time. Lesson: Password concepts
Exposure factor: Prioritize using: vulnerability classification (what kind of flaw and how severe), exposure factor (the percentage of the asset's value that would be lost if the flaw is exploited), environmental variables (is it… Lesson: Prioritize with context
Exposure factor (EF): Exposure factor (EF): the percentage of the asset's value lost in one event. Lesson: The money formulas
External: Compliance reporting can be internal (to management and the board, tracking how well rules are followed) or external (to regulators, card brands, customers). Lesson: Compliance reporting and consequences
F
Fail over: Fail over: actually switch to the backup system or site to prove it works. Lesson: Testing the plan
Fail-closed: Fail-closed: traffic stops, so security wins and availability loses. Lesson: Failure modes: fail-open vs fail-closed
Fail-open: Fail-open: traffic keeps flowing without inspection, so availability wins and security loses. Lesson: Failure modes: fail-open vs fail-closed
False negative: A false negative misses a vulnerability that is there (dangerous, because nobody fixes it). Lesson: Confirmation: false positives and false negatives
False positive: A false positive reports a vulnerability that is not really there (wastes time). Lesson: Confirmation: false positives and false negatives
Federation: Federation is trust between identity systems of different organizations: users log in with their home identity provider and get into a partner's apps. Lesson: Federation, SSO and interoperability
Fencing: Fencing marks a boundary and keeps people out (height and razor wire increase the strength). Lesson: Barriers: bollards, fencing, vestibules
File: File encryption protects individual files (Windows EFS). Lesson: Data at rest: from disk to record
File integrity monitoring (FIM): File integrity monitoring (FIM): alerts when important files change (system binaries, configs). Lesson: Endpoint and data capabilities
File system artifacts: New indicators include log manipulation (a cleared audit log), plaintext strings in malware, file system artifacts and altered timestamps. Lesson: New attacks and indicators of compromise
File-based: File-based: malicious documents and files such as PDFs with scripts, Office files with macros, compressed archives (ZIP, RAR) hiding executables. Lesson: Message-based, image-based, file-based
Fileless: A virus attaches to a file or program and needs a user to run it to spread (program, boot sector, script and macro viruses; fileless viruses live only in memory and use built-in tools like PowerShell). Lesson: Virus and worm
Financial gain: Organized crime groups are professional, well funded and driven by financial gain: ransomware, card theft, business email compromise, extortion. Lesson: Nation-state and organized crime
Financial information: Financial information: bank, payroll, accounting data. Lesson: Data types
Fines: Consequences of non-compliance: fines, sanctions (restrictions or penalties imposed by regulators or governments), reputational damage, loss of license (losing the right to operate or to process cards) and… Lesson: Compliance reporting and consequences
Firewall logs: Firewall logs: allowed and blocked connections (source, destination, port). Lesson: Log data
Firmware: Firmware is the low-level software in hardware (BIOS/UEFI, routers, cameras, drives). Lesson: Firmware, end-of-life, legacy
Forced entry: Objective 2.5 adds quishing (QR phishing), deepfake impersonation, skimming and forced entry, forgery attacks such as SSRF, and credential attacks like user enumeration and MFA bypass (push fatigue, stolen session… Lesson: New attacks and indicators of compromise
Forgery: Forgery makes a server or browser send requests the user didn't intend: cross-site request forgery (CSRF) abuses a logged-in user's browser; server-side request forgery (SSRF) makes a server fetch internal resources. Lesson: Privilege escalation, forgery, directory traversal
Frequency: Frequency: how often you back up sets the maximum data loss (ties to RPO). Lesson: Backups
Full-disk encryption (FDE): Full-disk encryption (FDE) encrypts the entire drive, including the OS, so a stolen laptop is unreadable (BitLocker, FileVault). Lesson: Data at rest: from disk to record
G
Gap analysis: A gap analysis compares the organization's current security posture with a target, usually a framework or standard such as the NIST Cybersecurity Framework or ISO/IEC 27001. Lesson: Where are we vs. where should we be?
Gateway: Gateway: an email security gateway filters spam, phishing, malware and data leaving by email. Lesson: Email security
Generator: A generator gives power for hours or days, but takes time to start, so the UPS bridges the gap until it does. Lesson: Power
Geographic dispersion: Geographic dispersion: put sites far enough apart that one disaster (storm, flood, regional outage) cannot hit both. Lesson: Site considerations
Geographic restrictions: Geographic restrictions limit where data can be accessed or stored (block logins from outside the US, keep EU data in EU regions). Lesson: Geographic restrictions, segmentation, permissions
Geolocation: Geolocation is knowing where a user or device physically is (GPS, IP location). Lesson: Data sovereignty and geolocation
Global: Governance must reflect the outside world: regulatory rules (agency requirements), legal obligations (laws and contracts), industry standards (PCI DSS for cards), and the scope of the law: local/regional (state or… Lesson: External considerations; monitoring and revision
gMSA: gMSA: a Windows service account whose password Active Directory rotates automatically. Lesson: Architecture and operations tools
Government entities: Government entities run governance for public agencies and set rules others must follow. Lesson: Types of governance structures
Group Policy: Group Policy centrally pushes security settings (password rules, firewall, lock screens, software restrictions) to Windows computers in an Active Directory domain. Lesson: Operating system security
Guard rails: Guard rails: automatic checks that block unsafe actions (no public storage buckets). Lesson: Use cases of automation and scripting
Guidelines: Guidelines are recommendations: helpful advice that is not mandatory. Lesson: Standards, procedures, guidelines
H
Hacktivist: A hacktivist attacks to push a philosophical or political cause: website defacement, DDoS, leaking documents. Lesson: Hacktivist and unskilled attacker
Hallucination: Hallucination: confident but false output (fake citations), dangerous if trusted blindly. Lesson: Poisoning, theft and leakage
Hard/soft authentication tokens: Hard/soft authentication tokens: a hard token is a physical device showing codes; a soft token is an app on a phone. Lesson: Multifactor authentication
Hardcoded secrets: New surfaces (2.4): hardcoded secrets, unsafe exception handling, stale credentials, rogue devices, LLMs, identity providers, public repositories and public object storage. Lesson: Vectors and attack surfaces added in V8
Hardening: Hardening reduces a system's attack surface. Lesson: Make each host harder to break
Hardware provider: Supply chain vulnerabilities come from your providers: a service provider with weak security and access to you, a hardware provider shipping counterfeit or tampered parts, a software provider whose code or update… Lesson: Cloud-specific and supply chain
Hardware security module (HSM): A hardware security module (HSM) is a dedicated, tamper-resistant appliance or card for large-scale key storage and fast crypto, often clustered with redundant power, used by CAs and payment systems. Lesson: TPM and HSM
Hashing: Hashing runs data through a one-way function that produces a fixed-length digest (a fingerprint). Lesson: Hashing
Heat map: The result is often a heat map, a floor plan colored by signal strength. Lesson: Wireless installation: site surveys and heat maps
High availability (HA): High availability (HA) means a system stays up nearly all the time, often measured in "nines". Lesson: High availability
Honeyfile: A honeyfile is a bait file with a tempting name, like passwords.xlsx, placed on a share; opening it raises an alert. Lesson: Honeyfiles and honeytokens
Honeynet: A honeynet is a larger network of honeypots (servers, workstations, routers) that looks like a real environment. Lesson: Honeypots and honeynets
Honeypot: A honeypot is a fake system built to attract attackers so you can watch their tools and methods while they waste time away from real assets. Lesson: Honeypots and honeynets
Honeytoken: A honeytoken is a traceable piece of fake data: a fake API key, a fake database record, a fake customer email address. Lesson: Honeyfiles and honeytokens
Horizontal: Privilege escalation gains more rights than intended: vertical (user to admin) or horizontal (one user to another user's data). Lesson: Privilege escalation, forgery, directory traversal
Host-based firewall: CompTIA lists: encryption (full-disk, files), installation of endpoint protection (antivirus/EDR), a host-based firewall that filters traffic on the device itself, a host-based intrusion prevention system (HIPS) that… Lesson: Make each host harder to break
Host-based intrusion prevention system (HIPS): CompTIA lists: encryption (full-disk, files), installation of endpoint protection (antivirus/EDR), a host-based firewall that filters traffic on the device itself, a host-based intrusion prevention system (HIPS) that… Lesson: Make each host harder to break
Hot site: Hot site: fully equipped, data replicated, ready in minutes to hours (most expensive). Lesson: Site considerations
Human approval: Human approval before an AI sends money, emails or deletes data. Lesson: Defenses
Human-readable: Human-readable (documents, screens) vs non-human-readable (binary, barcodes, encrypted blobs): both still need protection. Lesson: Data types
Hybrid: A hybrid cloud mixes on-premises systems with public cloud (or several clouds). Lesson: Hybrid considerations and third-party vendors
Hybrid/remote work environments: Hybrid/remote work environments: secure home Wi-Fi, VPN, privacy in public places. Lesson: User guidance and training topics
I
ICS/SCADA: ICS/SCADA: industrial control systems run physical processes (conveyors, HVAC, power). Lesson: IoT, ICS/SCADA, RTOS and embedded systems
Identification: Identification is claiming an identity (typing a username). Lesson: The AAA framework
Identity proofing: Identity proofing verifies a person really is who they claim (ID documents, background checks, in-person check) before issuing credentials. Lesson: Provisioning, permissions, identity proofing
Identity providers: New surfaces (2.4): hardcoded secrets, unsafe exception handling, stale credentials, rogue devices, LLMs, identity providers, public repositories and public object storage. Lesson: Vectors and attack surfaces added in V8
Image-based: Image-based: malicious content in images, such as an SVG holding HTML or JavaScript, data hidden with steganography, or a QR code leading to a phishing site. Lesson: Message-based, image-based, file-based
Impact: Qualitative analysis uses ratings like low/medium/high and a heat map of likelihood vs impact. Lesson: Qualitative vs quantitative
Impact analysis: Impact analysis asks what this change could break, how risky it is (often rated high, medium or low), and what the risk is of NOT making it. Lesson: Impact analysis and test results
Impersonation: Impersonation is pretending to be someone else, such as IT support, a vendor or an executive. Lesson: Impersonation, pretexting, BEC
Implicit trust zone: An implicit trust zone is the area past the gate where traffic is trusted for that session, so it should be as small as possible, ideally just the one resource. Lesson: Subjects, zones and the PEP
Impossible travel: Impossible travel: logins from places too far apart for the time between them (Detroit, then Lagos 30 minutes later). Lesson: Account clues
In transit: In transit: moving across a network (protect with TLS, IPSec, VPN). Lesson: Data states
In use: In use: loaded in memory and being processed (hardest to protect; trusted execution environments and memory protections help). Lesson: Data states
In-band: In-band means over the network, protected by asymmetric crypto. Lesson: Key exchange
Inability to patch: Inability to patch: the device cannot be updated at all. Lesson: Considerations: the trade-off checklist
Incident response: Incident response policy: who handles incidents and how they are reported. Lesson: Policies
Independent assessments: Independent assessments: reports from outside auditors (such as SOC 2 or ISO 27001 certification). Lesson: Vendor assessment
Independent third-party audit: An independent third-party audit is done by an outside firm with no stake in the result, giving the most trusted opinion. Lesson: External audits and assessments
Indirect: Indirect injection hides instructions in content the AI reads: a web page, email or document. Lesson: Prompt injection and jailbreaking
Industry: Governance must reflect the outside world: regulatory rules (agency requirements), legal obligations (laws and contracts), industry standards (PCI DSS for cards), and the scope of the law: local/regional (state or… Lesson: External considerations; monitoring and revision
industry/organizational impact: are there compensating controls?), industry/organizational impact (what a breach here would do to this business) and risk tolerance (how much risk the organization will accept and for how long). Lesson: Prioritize with context
Information security policies: Information security policies: the overall security rules of the organization. Lesson: Policies
Information-sharing organization: Information-sharing organization: groups (such as industry ISACs) where members share threats in their sector. Lesson: Threat feeds
Infrared: Infrared sensors detect heat (infrared radiation) from a body, used in motion detectors. Lesson: Sensors
Infrastructure: Capacity planning makes sure there is enough of three things when demand jumps or a site fails: people (enough trained staff, cross-training), technology (servers, licenses, app capacity) and infrastructure (power,… Lesson: Continuity of operations and capacity planning
Infrastructure as code: Infrastructure as code describes servers, networks and firewall rules in machine-readable template files that a tool deploys automatically. Lesson: Infrastructure as code (IaC)
Initial: Reporting and monitoring happen at two points: initial (a baseline measurement when the program starts) and recurring (regular measurements to show the trend). Lesson: Reporting, monitoring, development, execution
Injection: Injection attacks put attacker data into something that gets executed or interpreted: SQL, HTML/script (XSS), LDAP, XML, OS commands, DLLs. Lesson: Injection, buffer overflow, replay
Inline: Inline devices sit in the traffic path, so every packet goes through them (an IPS, a firewall). Lesson: Device attributes: active/passive, inline/tap
Input validation: Input validation: check every input on the server against what is allowed (type, length, format). Lesson: Application security
Insider threat: An insider threat is someone with authorized access (employee, contractor, partner) who misuses it, on purpose (revenge, money) or by carelessness. Lesson: Insider threat and shadow IT
Installation of endpoint protection: CompTIA lists: encryption (full-disk, files), installation of endpoint protection (antivirus/EDR), a host-based firewall that filters traffic on the device itself, a host-based intrusion prevention system (HIPS) that… Lesson: Make each host harder to break
Instant messaging (IM): Message-based vectors: email (phishing links and attachments), SMS text messages and instant messaging (IM) in chat apps. Lesson: Message-based, image-based, file-based
Insurance: Insurance: cyber insurance transfers some of the financial impact; it does not remove the flaw. Lesson: Response and remediation
Integrated: Integrated: attackers and defenders working together and sharing results (often called purple team). Lesson: Pen test types
Integrations and APIs: Integrations and APIs connect tools so they share data and act together. Lesson: Use cases of automation and scripting
Integrity: Integrity makes sure data is stored and moved without unauthorized change and that changes can be detected (hashing, digital signatures, certificates). Lesson: Confidentiality, integrity, availability
Intellectual property: Intellectual property: creations protected by copyright, patents and trademarks (logos, software). Lesson: Data types
Intelligence sources: Threats come from threat feeds and intelligence sources (OSINT, ISACs, government and commercial feeds), are ranked by likelihood and impact, and follow an intelligence life cycle. Lesson: Objective 2.1: threat and vulnerability characteristics
Internal: Compliance reporting can be internal (to management and the board, tracking how well rules are followed) or external (to regulators, card brands, customers). Lesson: Compliance reporting and consequences
Internal and external: Monitoring is both internal and external (your own checks plus auditors and regulators). Lesson: Compliance monitoring
Internal/external: Internal/external: inside the organization (insider, shadow IT) or outside it. Lesson: Attributes of actors
Interoperability: Interoperability is how well identity systems and apps work together, which depends on shared standards. Lesson: Federation, SSO and interoperability
Inventory: Inventory is the maintained list of assets: hardware, software and licenses, with owner, location and status. Lesson: Monitoring and asset tracking
IoT: IoT: smart devices (cameras, thermostats, scanners). Lesson: IoT, ICS/SCADA, RTOS and embedded systems
IoT devices: ICS/SCADA, embedded systems, RTOS and IoT devices: change defaults, segment, apply vendor firmware when available, compensate when not. Lesson: Hardening targets
IPAM: CSPM: continuous checks of cloud settings; IPAM: tracks IP space and finds hosts scans miss. Lesson: Architecture and operations tools
IPS/IDS: IPS/IDS: inspect traffic for attacks; the IPS blocks inline, the IDS alerts. Lesson: Network appliances
IPS/IDS logs: IPS/IDS logs: detected or blocked attack signatures. Lesson: Log data
IPSec: IPSec works at layer 3: AH gives integrity and authentication only, ESP adds encryption. Lesson: VPN, remote access and tunneling
Isolation: Isolation cuts a system off: quarantining an infected PC, or sandboxing an app. Lesson: Segmentation, access control, allow lists, isolation
J
Jailbreaking: Jailbreaking (iOS) or rooting (Android) removes the operating system's built-in restrictions to gain full control, which also disables protections and blocks updates or MDM controls. Lesson: Side loading and jailbreaking
Jamming: Wireless attacks include deauthentication floods that kick users off Wi-Fi (802.11w management frame protection helps), jamming of the radio frequencies, and evil twin or rogue access points that capture traffic. Lesson: DNS attacks and wireless attacks
Journaling: Journaling: logs every change so data can be replayed or rolled back to a precise point. Lesson: Backups: recovery, replication, journaling
Jump server: Jump server: a hardened host admins connect to first, then reach protected systems from it. Lesson: Network appliances
Just-in-time permissions: PAM tools control them: just-in-time permissions grant admin rights only when needed for a set period, then remove them; password vaulting stores privileged credentials in a vault where admins check them out (logged… Lesson: Privileged access management (PAM)
K
Key: The algorithm is the math (AES, RSA, ECC); the key is the secret input. Lesson: Algorithms and key length
Key escrow: Key escrow means a trusted third party (or a protected internal store) holds a copy of decryption keys, so data can be recovered if a key is lost or an employee leaves. Lesson: PKI and key escrow
Key exchange: Key exchange is how two sides end up with the same symmetric key. Lesson: Key exchange
Key length: Longer key length means more possible keys, so brute force takes much longer. Lesson: Algorithms and key length
Key management system (KMS): A key management system (KMS) centrally manages keys through their whole life: create, store, rotate, expire, revoke, and log every use, keeping keys separate from the data they protect. Lesson: Key management system and secure enclave
Key risk indicators: Key risk indicators (KRIs) are metrics that warn a risk is growing (number of unpatched critical systems). Lesson: Risk register
Key stretching: Key stretching makes a weak secret (like a password) stronger by running it through a hash or cipher many thousands of times, so every guess costs the attacker much more time. Lesson: Key stretching
Keylogger: A keylogger records keystrokes to steal passwords and messages; it can be software or a small hardware plug. Lesson: Spyware, keylogger, bloatware
Known environment: Known environment (white box): testers get full details (network diagrams, source code). Lesson: How much the testers know
L
Layer 4: Layer 4 firewall: filters on IP addresses, ports and protocol (TCP/UDP). Lesson: Firewall types
Layer 7: Layer 7 firewall: understands applications, so it can tell web browsing from a file-sharing app on the same port 443. Lesson: Firewall types
LDAP: LDAP: protocol to query and update a directory (users, groups); TCP 389, or LDAPS on 636 with TLS. Lesson: LDAP, SAML and OAuth
Least privilege: Least privilege gives users and services only the rights they need, for only as long as needed. Lesson: Patching, encryption, monitoring, least privilege
Least privilege for AI agents: Least privilege for AI agents: give the bot only the data and actions it needs. Lesson: Defenses
Legacy: Legacy systems are old platforms still in use because something depends on them, often running unsupported software and hard to secure. Lesson: Firmware, end-of-life, legacy
Legacy applications: Legacy applications are old systems that may not be supported, may lack documentation, and may break when anything around them changes, so treat changes near them carefully. Lesson: Legacy applications and dependencies
Legal: Governance must reflect the outside world: regulatory rules (agency requirements), legal obligations (laws and contracts), industry standards (PCI DSS for cards), and the scope of the law: local/regional (state or… Lesson: External considerations; monitoring and revision
Legal hold: Legal hold: an order to preserve all data related to a case; normal deletion and retention rules are suspended. Lesson: Digital forensics
Legal implications: Privacy laws have legal implications at each level: local/regional (state laws), national (country laws) and global (GDPR covers EU residents' data anywhere). Lesson: Privacy
Legal information: Legal information: contracts, court records, legal advice. Lesson: Data types
Length: Length: the strongest single factor; long passphrases beat short complex ones. Lesson: Password concepts
Lessons learned: Lessons learned: a review afterward to improve plans and controls. Lesson: The incident response process
Level of sophistication/capability: Level of sophistication/capability: from point-and-click tools to custom malware and zero-day exploits. Lesson: Attributes of actors
Life cycle: Threats come from threat feeds and intelligence sources (OSINT, ISACs, government and commercial feeds), are ranked by likelihood and impact, and follow an intelligence life cycle. Lesson: Objective 2.1: threat and vulnerability characteristics
Lighting: Lighting deters intruders and makes cameras useful; aim for even light with few shadows. Lesson: Eyes and IDs: video, guards, badges, lighting
Likelihood: Qualitative analysis uses ratings like low/medium/high and a heat map of likelihood vs impact. Lesson: Qualitative vs quantitative
Living-off-the-land: Endpoint-based: trusted devices, built-in tools and living-off-the-land tools. Lesson: Vectors and attack surfaces added in V8
LLMs: New surfaces (2.4): hardcoded secrets, unsafe exception handling, stale credentials, rogue devices, LLMs, identity providers, public repositories and public object storage. Lesson: Vectors and attack surfaces added in V8
LMS: Awareness (5.6): an LMS to deliver and track training, targeted and corrective training, personnel behavior risk scoring. Lesson: Program management additions
Load balancer: Load balancer: spreads requests across servers for availability and scale; can offload TLS. Lesson: Network appliances
Load balancing: Load balancing spreads requests across several independent servers; if one dies, the balancer stops sending it traffic. Lesson: High availability: load balancing vs clustering
local/regional: Governance must reflect the outside world: regulatory rules (agency requirements), legal obligations (laws and contracts), industry standards (PCI DSS for cards), and the scope of the law: local/regional (state or… Lesson: External considerations; monitoring and revision
Log aggregation: Log aggregation: collect logs from everywhere into one place in a common format. Lesson: Monitoring activities
Log manipulation: New indicators include log manipulation (a cleared audit log), plaintext strings in malware, file system artifacts and altered timestamps. Lesson: New attacks and indicators of compromise
Logic bomb: A logic bomb is code that waits for a trigger (a date, or an event like an employee being removed from payroll) and then does damage. Lesson: Logic bomb and rootkit
Logical segmentation: Logical segmentation separates traffic on shared hardware with VLANs, subnets and ACLs. Lesson: Physical isolation, logical segmentation, SDN
Logistics providers: Supply chain: third parties, MSPs, logistics providers and SaaS providers; plus OT, IoT and physical passes. Lesson: Vectors and attack surfaces added in V8
Loss of license: Consequences of non-compliance: fines, sanctions (restrictions or penalties imposed by regulators or governments), reputational damage, loss of license (losing the right to operate or to process cards) and… Lesson: Compliance reporting and consequences
M
Maintain: Maintain it: update it when patches, new threats or new versions arrive, and scan for drift away from it. Lesson: Secure baselines: establish, deploy, maintain
Maintenance window: A maintenance window is the agreed time when changes may be made with the least business impact (for a pet shop, maybe Tuesday 2 a.m.). Lesson: Backout plan, maintenance window, SOP
Malicious code: Malicious code covers harmful scripts, macros and executables used to gain or keep access. Lesson: On-path, credential replay, malicious code
Malicious update: A malicious update is an update that carries malware, because an attacker compromised the vendor's build or update server, or tricked the app into downloading from a fake source. Lesson: Malicious update
Managed service providers (MSPs): Managed service providers (MSPs) often hold remote admin access to many customers at once, so one breached MSP opens many doors. Lesson: Supply chain
Managerial + directive: A compliance policy is managerial + directive. Lesson: One control, two labels
Managerial controls: Managerial controls (also called administrative) are about governing security: policies, risk assessments, security plans, onboarding rules for vendors. Lesson: Technical and managerial
Mandatory: Mandatory (MAC): the system enforces labels and clearances (Secret, Top Secret); users cannot change them. Lesson: Access control models
Masking: Masking hides part of the data when shown (a card number shown as XXXX XXXX XXXX 4417). Lesson: Masking, tokenization, obfuscation
Mean time between failures (MTBF): Mean time between failures (MTBF): average running time between failures (reliability). Lesson: Risk reporting and business impact analysis
Mean time to repair (MTTR): Mean time to repair (MTTR): average time to fix a failed component. Lesson: Risk reporting and business impact analysis
Memory injection: Memory injection puts malicious code into the memory space of a running, trusted process (for example DLL injection on Windows), so it runs with that process's rights and hides inside it. Lesson: Memory injection and buffer overflow
Message-based: Message-based vectors: email (phishing links and attachments), SMS text messages and instant messaging (IM) in chat apps. Lesson: Message-based, image-based, file-based
Metadata: Metadata: data about data (email headers, file timestamps and authors, photo location). Lesson: Log data
MFA bypass: Objective 2.5 adds quishing (QR phishing), deepfake impersonation, skimming and forced entry, forgery attacks such as SSRF, and credential attacks like user enumeration and MFA bypass (push fatigue, stolen session… Lesson: New attacks and indicators of compromise
Microservices: Microservices split an app into small independent services that talk over APIs. Lesson: Serverless and microservices
Microwave: Microwave sensors send microwave pulses and detect movement from the reflections; they cover larger areas than infrared. Lesson: Sensors
Misconfiguration: Misconfiguration: insecure settings such as open file permissions, default accounts left enabled, unneeded services and ports on, debug mode on in production, cloud storage set to public. Lesson: Cryptographic and misconfiguration
Misinformation: Misinformation is false information shared without intent to deceive. Lesson: Misinformation and disinformation
Missing logs: Missing logs: gaps in logs or cleared logs, because attackers delete evidence. Lesson: Log and publication clues
Mitigate: Mitigate: add controls to reduce likelihood or impact. Lesson: Risk management strategies
MITRE ATT&CK: Audits (5.5): MITRE ATT&CK (tactics and techniques), Cyber Kill Chain (seven phases), Diamond Model (adversary, capability, infrastructure, victim), audit charter, sampling and assertions. Lesson: Program management additions
MOA: MOA (memorandum of agreement): more formal; parties agree to specific conditions and roles. Lesson: Agreement types
Mobile device management (MDM): Mobile device management (MDM) pushes policies to phones and tablets: passcodes, encryption, approved apps, remote wipe, separating work and personal data. Lesson: Mobile solutions
Mobile devices: Mobile devices: screen lock, encryption, MDM, app store only. Lesson: Hardening targets
Model inversion: Model inversion: querying a model to reconstruct sensitive training data about people. Lesson: Poisoning, theft and leakage
Model theft (extraction): Model theft (extraction): mass queries used to build a copy of a paid model. Lesson: Poisoning, theft and leakage
Monitoring: Monitoring (SIEM, EDR, log review) finds what other controls miss. Lesson: Patching, encryption, monitoring, least privilege
Monitoring and revision: Monitoring and revision: review documents on a schedule and after major changes, incidents or new laws, so they never go stale. Lesson: External considerations; monitoring and revision
Motivations: CompTIA lists these motivations. Lesson: Why they attack
MOU: MOU (memorandum of understanding): a statement of intent between parties; usually not legally binding. Lesson: Agreement types
MSA: MSA (master service agreement): general legal terms for all future work together. Lesson: Agreement types
Multi-cloud: Multi-cloud spreads workloads across more than one cloud provider, so a single provider's outage or failure does not stop the business. Lesson: Platform diversity and multi-cloud
N
NAC: NAC (network access control): checks a device's identity and health (patches, AV) before letting it on the network. Lesson: Endpoint and data capabilities
Nation-state: A nation-state actor works for a government: the most resources and the highest sophistication, patient long-term campaigns called advanced persistent threats (APTs), motives like espionage, data exfiltration,… Lesson: Nation-state and organized crime
National: Governance must reflect the outside world: regulatory rules (agency requirements), legal obligations (laws and contracts), industry standards (PCI DSS for cards), and the scope of the law: local/regional (state or… Lesson: External considerations; monitoring and revision
NDA: NDA (non-disclosure agreement): keeps shared information confidential. Lesson: Agreement types
NetFlow: NetFlow: records flow metadata (who talked to whom, ports, how much), not packet contents. Lesson: Monitoring tools, part 2
Network logs: Network logs: switches, routers, DNS, DHCP, proxies. Lesson: Log data
Neutral: It can be expansionary (willing to take more risk for growth), conservative (prefers low risk) or neutral (balanced). Lesson: Tolerance and appetite
NGFW: NGFW (next-generation firewall): Layer 7 app awareness plus IPS, URL filtering and often user identity. Lesson: Firewall types
Non-human-readable: Human-readable (documents, screens) vs non-human-readable (binary, barcodes, encrypted blobs): both still need protection. Lesson: Data types
Non-repudiation: Non-repudiation means someone cannot credibly deny they did something, such as sending a message or approving a payment. Lesson: Non-repudiation
O
OAuth: OAuth: an authorization framework; it gives an app a token to act on your behalf without your password. Lesson: LDAP, SAML and OAuth
Obfuscation: Obfuscation makes data hard to understand or find without necessarily encrypting it. Lesson: Steganography
OCSP stapling: With OCSP stapling the server attaches a fresh, CA-signed OCSP response to the handshake. Lesson: Revocation: CRL and OCSP
Offensive: Offensive: attacking the organization like a real adversary (red team). Lesson: Pen test types
Offline: Brute force tries many passwords against one account: online against the live login (lockouts stop it) or offline against stolen hashes at full speed (lockouts don't help; salting and key stretching do). Lesson: Password spraying and brute force
On-path: An on-path attack (formerly man-in-the-middle) puts the attacker between two parties to read or change traffic, for example with ARP poisoning on a LAN. Lesson: On-path, credential replay, malicious code
On-premises: On-premises: you own and run everything, so you get full control and full responsibility (power, patching, physical security, staff, cost). Lesson: On-premises, centralized or decentralized
onboarding/offboarding: Procedures are step-by-step instructions: the change management procedure, onboarding/offboarding checklists, and playbooks (step-by-step responses to a specific incident type). Lesson: Standards, procedures, guidelines
One-time: Risk assessments can be ad hoc (for a specific event, like a new vendor), recurring (on a schedule, such as yearly), one-time (for a single project) or continuous (ongoing, automated monitoring of risk). Lesson: Identification and assessment types
Ongoing supportability: Automation has costs too: complexity (more moving parts to understand), cost (tools, development time), a single point of failure (if the automation platform breaks, everything it does stops), technical debt (quick… Lesson: Other considerations
Online: Brute force tries many passwords against one account: online against the live login (lockouts stop it) or offline against stolen hashes at full speed (lockouts don't help; salting and key stretching do). Lesson: Password spraying and brute force
Online Certificate Status Protocol (OCSP): Online Certificate Status Protocol (OCSP) lets a client ask about one certificate and get good, revoked or unknown in real time. Lesson: Revocation: CRL and OCSP
Onsite/offsite: Onsite/offsite: onsite restores fast; offsite (or cloud) survives a site disaster. Lesson: Backups
Open public ledger: An open public ledger means every participant holds a copy and can verify it, so there is no single place to tamper with. Lesson: Blockchain and the open public ledger
Open service port: Every open service port is a listening service an attacker can probe, and each needs to be needed, patched and filtered; close the rest. Lesson: Open service ports and default credentials
Operational + preventive: A guard shack at the gate is operational + preventive. Lesson: One control, two labels
Operational controls: Operational controls are carried out by people as part of their routine: security guards doing rounds, awareness training, a help desk following an ID-check script, daily log review. Lesson: Operational and physical
Operational security: Operational security: not leaking useful details (schedules, badge photos on social media). Lesson: User guidance and training topics
opt-in vs. opt-out: Privacy (5.4): **opt-in vs. Lesson: Program management additions
Organized crime: Organized crime groups are professional, well funded and driven by financial gain: ransomware, card theft, business email compromise, extortion. Lesson: Nation-state and organized crime
OS-based vulnerabilities: Operating systems are huge and complex, so OS-based vulnerabilities keep appearing: privilege escalation bugs, remote code execution in network services, kernel flaws. Lesson: Operating system (OS)-based
OS-specific security logs: OS-specific security logs: Windows Security log (4624 logon, 4625 failed logon, 4720 account created), Linux auth logs. Lesson: Log data
OSINT: OSINT (open-source intelligence): free public sources such as advisories, vendor bulletins and security blogs. Lesson: Threat feeds
Out-of-band: Out-of-band means sending it another way (in person, by phone, by courier). Lesson: Key exchange
Out-of-band management: Out-of-band management: a separate path to manage devices when the main network is down or hostile. Lesson: Architecture and operations tools
Out-of-cycle logging: Out-of-cycle logging: log entries at unexpected times, such as patching or admin activity at 3 a.m. Lesson: Log and publication clues
Owner: The owner is the person or team accountable for the change and its result, usually the one asking for it; they may not do the technical work. Lesson: Approval, ownership, stakeholders
Owners: Owners: senior people accountable for a data set or system; they set its classification and who may access it. Lesson: Roles for systems and data
Ownership: Assignment/accounting: every asset gets ownership: an owner, a person accountable for it, and a classification (how sensitive or critical it is), which decides how it must be protected. Lesson: Acquisition and assignment
P
Package monitoring: For applications: static analysis reviews source code without running it; dynamic analysis tests the running app (including fuzzing with unexpected input); package monitoring tracks the third-party libraries and… Lesson: Vulnerability scans and application testing
Packet captures: Packet captures hold the full contents of network traffic: the most detail, but large, and encrypted traffic needs decryption to read. Lesson: Other data sources
PAM tools: PAM tools control them: just-in-time permissions grant admin rights only when needed for a set period, then remove them; password vaulting stores privileged credentials in a vault where admins check them out (logged… Lesson: Privileged access management (PAM)
Parallel processing: Parallel processing: run the primary and backup systems at the same time on the same work and compare results. Lesson: Testing the plan
Parameterized queries: The fixes are parameterized queries (prepared statements), input validation and least-privilege database accounts. Lesson: SQL injection (SQLi)
Partially known environment: Partially known environment (gray box): some details, like a normal user account. Lesson: How much the testers know
Partition: Partition encryption covers one partition of a disk. Lesson: Data at rest: from disk to record
Pass the hash: Credential replay captures login data (a password hash, a token) and reuses it to log in without knowing the password; pass the hash is an example. Lesson: On-path, credential replay, malicious code
Passive: A passive device only watches and reports. Lesson: Device attributes: active/passive, inline/tap
Passkeys: Identity (4.5) adds identity proofing before accounts are issued, emergency access (break-glass) accounts, backup codes, passkeys (phishing-resistant FIDO2 keys), time-based access and compromised credential monitoring. Lesson: Identity, automation and AI in operations
Password: Standards are mandatory, specific requirements that support a policy: password standards (length, MFA), access control standards, physical security standards (badges, locks), encryption standards (AES-256, TLS 1.2+). Lesson: Standards, procedures, guidelines
Password management: Password management: unique passphrases, password managers, MFA. Lesson: User guidance and training topics
Password managers: Password managers generate and store unique passwords. Lesson: Password concepts
Password vaulting: PAM tools control them: just-in-time permissions grant admin rights only when needed for a set period, then remove them; password vaulting stores privileged credentials in a vault where admins check them out (logged… Lesson: Privileged access management (PAM)
Passwordless: Passwordless (passkeys, FIDO2, biometrics) removes the password entirely. Lesson: Password concepts
Patch availability: Patch availability: does the vendor still ship fixes? Lesson: Considerations: the trade-off checklist
Patching: Patching fixes known vulnerabilities; make it fast, tested and tracked, including firmware and third-party apps. Lesson: Patching, encryption, monitoring, least privilege
PBKDF2: Examples: PBKDF2 and bcrypt (scrypt and Argon2 also add memory cost). Lesson: Key stretching
Penetration testing: Penetration testing goes beyond scanning: testers actually try to exploit flaws to prove impact. Lesson: Pen tests, disclosure programs and audits
People: Capacity planning makes sure there is enough of three things when demand jumps or a site fails: people (enough trained staff, cross-training), technology (servers, licenses, app capacity) and infrastructure (power,… Lesson: Continuity of operations and capacity planning
Permission restrictions: Permission restrictions grant access only to the people and services that need it, using ACLs, roles and least privilege. Lesson: Geographic restrictions, segmentation, permissions
Permissions: Access control limits who and what reaches a resource: access control lists (ACLs) on routers, firewalls and files, and permissions (read, write, execute) on data. Lesson: Segmentation, access control, allow lists, isolation
Personnel behavior risk scoring: Awareness (5.6): an LMS to deliver and track training, targeted and corrective training, personnel behavior risk scoring. Lesson: Program management additions
Philosophical or political: A hacktivist attacks to push a philosophical or political cause: website defacement, DDoS, leaking documents. Lesson: Hacktivist and unskilled attacker
Philosophical/political beliefs: Philosophical/political beliefs: a cause. Lesson: Why they attack
Phishing: Phishing uses fraudulent messages, usually email, to trick people into clicking, opening or revealing information; spear phishing targets specific people. Lesson: Phishing, vishing, smishing
Physical: Physical: tests doors, locks, badges and people (can a tester walk into the server room?). Lesson: Pen test types
Physical + compensating: A backup generator that keeps power on when the utility fails is physical + compensating. Lesson: One control, two labels
Physical + detective: A camera is physical + detective. Lesson: One control, two labels
Physical controls: Physical controls protect places and hardware you can touch: fences, locks, bollards, badge readers, a locked server cage. Lesson: Operational and physical
Physical isolation: Physical isolation uses separate hardware with no shared links. Lesson: Physical isolation, logical segmentation, SDN
Physical security: Standards are mandatory, specific requirements that support a policy: password standards (length, MFA), access control standards, physical security standards (badges, locks), encryption standards (AES-256, TLS 1.2+). Lesson: Standards, procedures, guidelines
Plaintext strings: New indicators include log manipulation (a cleared audit log), plaintext strings in malware, file system artifacts and altered timestamps. Lesson: New attacks and indicators of compromise
Platform diversity: Platform diversity uses different operating systems, vendors or technologies so one vulnerability or bug cannot take down everything. Lesson: Platform diversity and multi-cloud
Playbooks: Procedures are step-by-step instructions: the change management procedure, onboarding/offboarding checklists, and playbooks (step-by-step responses to a specific incident type). Lesson: Standards, procedures, guidelines
Policy: A policy is a high-level, mandatory statement of management intent: what must happen and why, approved by leadership. Lesson: Policies
Policy Administrator (PA): The Policy Administrator (PA) carries the decision out: it tells the enforcement point to open or close the path and creates the session credentials or tokens. Lesson: Policy Engine and Policy Administrator
Policy Enforcement Point (PEP): The Policy Enforcement Point (PEP) is the gatekeeper in the data path: it lets the subject's traffic through or blocks it, following what the PA tells it. Lesson: Subjects, zones and the PEP
Policy Engine (PE): The Policy Engine (PE) makes the decision: it weighs policy, identity, device posture and threat intel, then grants, denies or revokes access. Lesson: Policy Engine and Policy Administrator
Policy-driven access control: Policy-driven access control means access rules are written centrally as policy and applied the same way everywhere. Lesson: Control plane ideas
Policy/handbooks: Policy/handbooks: the rules, written so staff can find them. Lesson: User guidance and training topics
Port selection: Port selection: use the right, expected port for the secure service and close the insecure one. Lesson: Implementation of secure protocols
ports/protocols: Allow only the needed ports/protocols (443 for HTTPS, 22 for SSH) from the needed sources. Lesson: Firewalls: rules, ACLs, ports, screened subnets
Posture: Rate limiting, captive portals, endpoint posture checks and secrets scanning of repositories. Lesson: Architecture and operations tools
Power: Power: electricity and cooling needs. Lesson: Considerations: the trade-off checklist
Predictive analysis: Automation (4.6) adds AI: agentic AI acts on its own, a chatbot answers questions, predictive analysis forecasts, and AI-augmented baselines learn what normal looks like. Lesson: Identity, automation and AI in operations
Preparation: Preparation: plans, contacts, tools, training, before anything happens. Lesson: The incident response process
Preservation: Preservation: keep evidence unchanged (write blockers, hashes, secure storage). Lesson: Digital forensics
Pressure: Pressure sensors detect a change in force, such as a footstep on a floor mat or a window being pushed. Lesson: Sensors
Pretexting: Pretexting is the invented story that makes the request believable ("I'm from the auditors and need the payroll file by noon"). Lesson: Impersonation, pretexting, BEC
Prevention: opt-out, data correction, processing restrictions and prevention, AML/CTF and anti-bribery** training. Lesson: Program management additions
Preventive control: A preventive control stops an event before it happens: a door lock, a firewall deny rule, removing admin rights. Lesson: Preventive and deterrent
Prioritize: Prioritize using: vulnerability classification (what kind of flaw and how severe), exposure factor (the percentage of the asset's value that would be lost if the flaw is exploited), environmental variables (is it… Lesson: Prioritize with context
Prioritized: Vulnerabilities get a CVE ID, a CVSS score and a type (CWE), then get prioritized in context. Lesson: Objective 2.1: threat and vulnerability characteristics
Private: Private: about a person or for internal use, not for outsiders (employee details). Lesson: Data classifications
Private key: The public key can be shared with anyone; the private key is kept secret by its owner. Lesson: Asymmetric encryption
Privilege escalation: Privilege escalation gains more rights than intended: vertical (user to admin) or horizontal (one user to another user's data). Lesson: Privilege escalation, forgery, directory traversal
Probability: Probability is the measurable chance (often a percentage) that an event happens; likelihood is the same idea, often rated rather than measured. Lesson: Qualitative vs quantitative
Procedures: Procedures are step-by-step instructions: the change management procedure, onboarding/offboarding checklists, and playbooks (step-by-step responses to a specific incident type). Lesson: Standards, procedures, guidelines
Processing restrictions: opt-out, data correction, processing restrictions and prevention, AML/CTF and anti-bribery** training. Lesson: Program management additions
Processor: The controller decides why and how personal data is processed; the processor processes it for the controller. Lesson: Privacy
Processors: Processors: process personal data on behalf of a controller (a payroll service provider). Lesson: Roles for systems and data
Prompt injection: Prompt injection hides instructions in input so an AI model follows the attacker instead of its developers. Lesson: Prompt injection and jailbreaking
Proof of integrity: It needs two proofs: proof of integrity (the message was not changed, shown with a hash) and proof of origin (it came from this sender, shown with a digital signature made with the sender's private key). Lesson: Non-repudiation
Proof of origin: It needs two proofs: proof of integrity (the message was not changed, shown with a hash) and proof of origin (it came from this sender, shown with a digital signature made with the sender's private key). Lesson: Non-repudiation
Proprietary/third-party: Proprietary/third-party: paid feeds from security vendors, often curated and correlated. Lesson: Threat feeds
Protocol selection: Protocol selection: use the secure version (SSH not Telnet, SFTP not FTP, HTTPS not HTTP, LDAPS not LDAP, SNMPv3 not v1/v2c). Lesson: Implementation of secure protocols
Provisioning/de-provisioning user accounts: Provisioning/de-provisioning user accounts: create accounts with the right access on day one and disable them the moment someone leaves (a forgotten account is an open door). Lesson: Provisioning, permissions, identity proofing
Proxy server: Proxy server: makes requests on behalf of clients (forward proxy) or servers (reverse proxy); can cache, filter and hide addresses. Lesson: Network appliances
Public: Public: no harm if disclosed (store hours, press releases). Lesson: Data classifications
Public key: The public key can be shared with anyone; the private key is kept secret by its owner. Lesson: Asymmetric encryption
Public key infrastructure (PKI): Public key infrastructure (PKI) is the whole system of policies, people, hardware, software and certificate authorities that creates, distributes, manages, stores and revokes digital certificates, which bind a public… Lesson: PKI and key escrow
Published/documented: Published/documented: the attack or your data shows up publicly, such as your customer data for sale on a forum, or an attacker or researcher documenting the breach online. Lesson: Log and publication clues
Q
Qualitative: Qualitative analysis uses ratings like low/medium/high and a heat map of likelihood vs impact. Lesson: Qualitative vs quantitative
Quantitative: Quantitative analysis uses numbers and money. Lesson: Qualitative vs quantitative
Quarantine: Alert response and remediation/validation: act on alerts, for example quarantine an infected host, then confirm it is fixed. Lesson: Monitoring activities
Questionnaires: Questionnaires collect a vendor's answers about its controls in a standard format. Lesson: Vendor selection, questionnaires, monitoring, rules of engagement
Quishing: Objective 2.5 adds quishing (QR phishing), deepfake impersonation, skimming and forced entry, forgery attacks such as SSRF, and credential attacks like user enumeration and MFA bypass (push fatigue, stolen session… Lesson: New attacks and indicators of compromise
R
Race condition: A race condition is a flaw where the result depends on the timing of events. Lesson: Race conditions: TOC/TOU
Radio frequency identification (RFID) cloning: Radio frequency identification (RFID) cloning copies the data from an access badge with a hidden reader, sometimes just by standing close, then writes it to a blank card. Lesson: Brute force, RFID cloning, environmental
Rainbow tables: Many users pick the same password, so plain hashes would match, and attackers use rainbow tables (precomputed hashes) to look them up. Lesson: Salting
Ransomware: Ransomware encrypts files or systems and demands payment for the key; many groups also steal data first and threaten to publish it (double extortion). Lesson: Trojan and ransomware
Rate limiting: Rate limiting, captive portals, endpoint posture checks and secrets scanning of repositories. Lesson: Architecture and operations tools
RCS: Message-based: email, SMS, RCS, instant messaging and collaboration tools. Lesson: Vectors and attack surfaces added in V8
Reaction time: Why automate: efficiency/time saving; enforcing baselines and standard infrastructure configurations (no drift, no typos); scaling in a secure manner (100 servers built as safely as one); employee retention (fewer… Lesson: Benefits
Record: Record encryption protects individual records or columns, such as only the card-number field. Lesson: Data at rest: from disk to record
Recovery: Recovery: test restores regularly; a backup you cannot restore is not a backup. Lesson: Backups: recovery, replication, journaling
Recovery point objective (RPO): Recovery point objective (RPO): maximum acceptable data loss, measured in time (back up at least that often). Lesson: Risk reporting and business impact analysis
Recovery time objective (RTO): Recovery time objective (RTO): target time to get a system back after an outage. Lesson: Risk reporting and business impact analysis
Recurring: Risk assessments can be ad hoc (for a specific event, like a new vendor), recurring (on a schedule, such as yearly), one-time (for a single project) or continuous (ongoing, automated monitoring of risk). Lesson: Identification and assessment types
Reflected: Reflected (non-persistent) XSS bounces script in a crafted link off the server; stored (persistent) XSS saves it in the site, such as a product review, to hit everyone who views it. Lesson: Cross-site scripting (XSS)
Regulated: Regulated: controlled by law or industry rules (card numbers under PCI DSS, health data, personal data under privacy laws). Lesson: Data types
Regulatory: Governance must reflect the outside world: regulatory rules (agency requirements), legal obligations (laws and contracts), industry standards (PCI DSS for cards), and the scope of the law: local/regional (state or… Lesson: External considerations; monitoring and revision
Remote access: Remote access VPNs connect one user to the company; site-to-site VPNs connect whole networks. Lesson: VPN, remote access and tunneling
Removable devices: Removable devices such as USB drives can carry malware, act as a keyboard that types commands, or be left in a parking lot hoping someone plugs one in (baiting). Lesson: Voice call and removable device
Removal of unnecessary software: CompTIA lists: encryption (full-disk, files), installation of endpoint protection (antivirus/EDR), a host-based firewall that filters traffic on the device itself, a host-based intrusion prevention system (HIPS) that… Lesson: Make each host harder to break
Replay: A replay attack captures valid traffic, such as a session cookie or token, and sends it again to impersonate the user; that is how session hijacking works. Lesson: Injection, buffer overflow, replay
Replication: Replication: copies data to another system in near real time. Lesson: Backups: recovery, replication, journaling
Reporting: Then reporting: share status with owners and leadership: what was found, what was fixed, what is accepted and the trend over time. Lesson: Validation and reporting
Reporting and monitoring: Reporting and monitoring happen at two points: initial (a baseline measurement when the program starts) and recurring (regular measurements to show the trend). Lesson: Reporting, monitoring, development, execution
Reputation: Reputation: scores sites by their history; block low-reputation domains. Lesson: Web filtering
Reputational damage: Consequences of non-compliance: fines, sanctions (restrictions or penalties imposed by regulators or governments), reputational damage, loss of license (losing the right to operate or to process cards) and… Lesson: Compliance reporting and consequences
Rescanning: Validation of remediation: rescanning to confirm the finding is gone, an audit to check the change was made correctly, and verification (testing directly, for example confirming the patched version is running). Lesson: Validation and reporting
Resilience: Resilience: does it keep working when parts fail? Lesson: Considerations: the trade-off checklist
Resource consumption: Resource consumption: unusual CPU, memory, disk or bandwidth use, such as a server pegged at 100% at night (crypto-mining, exfiltration). Lesson: System and content clues
Resource inaccessibility: Resource inaccessibility: services, files or accounts suddenly can't be reached (ransomware encryption, DoS, changed passwords). Lesson: System and content clues
Resource provisioning: User provisioning and resource provisioning: create accounts and servers from templates, the same way every time. Lesson: Use cases of automation and scripting
Resource reuse: Resource reuse is when memory, storage or other resources given back by one VM are handed to another without being cleared, so data can leak between VMs. Lesson: VM escape and resource reuse
Resources/funding: Resources/funding: money, people and time (nation-states and organized crime are rich; unskilled attackers are not). Lesson: Attributes of actors
Responsibility matrix: The responsibility matrix (shared responsibility model) lists who secures each layer. Lesson: The responsibility matrix
Responsible disclosure program: A responsible disclosure program tells outside researchers how to report flaws privately so you can fix them before they go public. Lesson: Pen tests, disclosure programs and audits
Responsiveness: Responsiveness: how fast it answers users. Lesson: Considerations: the trade-off checklist
Restricted: Restricted: highest handling rules; very limited access (card data, trade secrets). Lesson: Data classifications
Restricted activities: Restricted activities means the change has a defined scope: the technician does only what was approved. Lesson: Allow/deny lists and restricted activities
Retention: A data inventory lists what personal data you hold and where; retention keeps it only as long as needed. Lesson: Privacy
Revenge: Revenge: getting back at someone. Lesson: Why they attack
RFI: RFI (what can vendors do?), RFP (detailed proposals), RFQ (prices for a defined order), EOI (who is interested?). Lesson: Program management additions
RFP: RFI (what can vendors do?), RFP (detailed proposals), RFQ (prices for a defined order), EOI (who is interested?). Lesson: Program management additions
RFQ: RFI (what can vendors do?), RFP (detailed proposals), RFQ (prices for a defined order), EOI (who is interested?). Lesson: Program management additions
Right to be forgotten: The right to be forgotten lets a data subject ask for their data to be erased. Lesson: Privacy
Right-to-audit clause: Right-to-audit clause: contract term letting you audit the vendor's security. Lesson: Vendor assessment
Risk appetite: Risk appetite is how much risk the organization is willing to take on to pursue its goals. Lesson: Tolerance and appetite
Risk assessments: Risk assessments can be ad hoc (for a specific event, like a new vendor), recurring (on a schedule, such as yearly), one-time (for a single project) or continuous (ongoing, automated monitoring of risk). Lesson: Identification and assessment types
Risk identification: Risk identification finds what could go wrong: threats, vulnerabilities and the assets at stake. Lesson: Identification and assessment types
Risk owners: Risk owners are the people accountable for each risk. Lesson: Risk register
Risk register: The risk register is the central list of risks: description, likelihood, impact, owner, strategy and status. Lesson: Risk register
Risk reporting: Risk reporting tells leadership the current risks, trends and decisions needed. Lesson: Risk reporting and business impact analysis
Risk threshold: A risk threshold is the level at which a risk or KRI triggers action. Lesson: Risk register
Risk tolerance: are there compensating controls?), industry/organizational impact (what a breach here would do to this business) and risk tolerance (how much risk the organization will accept and for how long). Lesson: Prioritize with context
Risk transference: Risk transference: does it move some risk to a provider or insurer? Lesson: Considerations: the trade-off checklist
Risky: Risky: actions that invite trouble (sharing passwords, disabling antivirus, plugging in a found USB). Lesson: Anomalous behavior recognition
Role-based: Role-based (RBAC): rights come from job roles (Cashier, Warehouse Lead). Lesson: Access control models
Root cause analysis: Root cause analysis asks why the incident happened, not just what happened (the phishing email was the trigger, but missing attachment sandboxing was the root cause). Lesson: Root cause analysis and threat hunting
Root of trust: A root of trust is the component everything else relies on and that is trusted by default. Lesson: Root of trust and the chain
Rooting: Jailbreaking (iOS) or rooting (Android) removes the operating system's built-in restrictions to gain full control, which also disables protections and blocks updates or MDM controls. Lesson: Side loading and jailbreaking
Rootkit: A rootkit hides deep in the system, often in the kernel, to conceal itself and other malware from the OS and security tools, so normal scans look clean. Lesson: Logic bomb and rootkit
Routers: Switches and routers: change default creds, disable unused ports and services, SSH not Telnet, secure management access. Lesson: Hardening targets
RTOS: RTOS: a real-time OS must respond within strict, predictable time limits (brakes, robot arms). Lesson: IoT, ICS/SCADA, RTOS and embedded systems
Rule-based: Rule-based: admin-defined rules apply to everyone (allow VPN only from managed devices). Lesson: Access control models
Rules: Firewall rules and access lists (ACLs) are read top-down; the first match wins, with an implicit deny at the end. Lesson: Firewalls: rules, ACLs, ports, screened subnets
Rules of engagement: Rules of engagement set what is allowed when testing or working with a vendor: scope, timing, contacts and limits. Lesson: Vendor selection, questionnaires, monitoring, rules of engagement
S
SAE: WPA3 replaces WPA2's pre-shared key exchange with SAE, which resists offline password guessing and gives forward secrecy; protected management frames are required. Lesson: Wireless security settings
Salt: A salt is a random value added to each password before hashing, stored next to the hash. Lesson: Salting
SAML: SAML: XML assertions from an identity provider (IdP) to a service provider (SP); classic enterprise web SSO. Lesson: LDAP, SAML and OAuth
Sanctions: Consequences of non-compliance: fines, sanctions (restrictions or penalties imposed by regulators or governments), reputational damage, loss of license (losing the right to operate or to process cards) and… Lesson: Compliance reporting and consequences
Sandboxing: Sandboxing runs code in an isolated environment with no access to the real system: test new apps, open suspicious attachments, detonate malware safely. Lesson: Sandboxing and monitoring
Sanitization: Sanitization: wipe data so it cannot be recovered, leaving the media reusable (overwrite, secure erase, cryptographic erase). Lesson: Disposal and decommissioning
SASE: SASE (secure access service edge) moves security to the cloud edge, close to users wherever they are. Lesson: SD-WAN and SASE
Scalability: Scalability: can it grow or shrink with demand? Lesson: Considerations: the trade-off checklist
Scaling in a secure manner: Why automate: efficiency/time saving; enforcing baselines and standard infrastructure configurations (no drift, no typos); scaling in a secure manner (100 servers built as safely as one); employee retention (fewer… Lesson: Benefits
Scanning: Scanning: regular vulnerability and config scans. Lesson: Monitoring activities
SCAP: SCAP (Security Content Automation Protocol): NIST standards that let tools check configurations and vulnerabilities automatically in a common language. Lesson: Monitoring tools, part 1
Screened subnet: Put public servers in a screened subnet (DMZ) between the internet and the internal network, so a compromised web server still cannot reach inside freely. Lesson: Firewalls: rules, ACLs, ports, screened subnets
SD-WAN: SD-WAN (software-defined WAN) links branch sites over any mix of connections (broadband, LTE, MPLS) and picks the best path by policy, often straight to cloud apps. Lesson: SD-WAN and SASE
Secrets scanning: Rate limiting, captive portals, endpoint posture checks and secrets scanning of repositories. Lesson: Architecture and operations tools
Secure baseline: A secure baseline is the approved, documented secure configuration for a type of system. Lesson: Secure baselines: establish, deploy, maintain
Secure cookies: Secure cookies: the Secure attribute sends the cookie only over HTTPS; HttpOnly hides it from scripts; SameSite limits cross-site sending. Lesson: Application security
Secure enclave: A secure enclave is a dedicated security processor built into a phone or computer, isolated from the main processor and OS, that protects secrets such as biometric data and device keys even if the OS is compromised. Lesson: Key management system and secure enclave
Security control: A security control is any safeguard that lowers risk to systems, data or people. Lesson: What a security control is
Security groups: Security groups: apply firewall-like rules automatically. Lesson: Use cases of automation and scripting
Security guard: A security guard can make judgment calls, check IDs and respond; two-person integrity/control means two guards are needed so no one person can be compromised. Lesson: Eyes and IDs: video, guards, badges, lighting
Security keys: Security keys are hardware keys (USB/NFC, FIDO2) that prove possession with cryptography and resist phishing. Lesson: Multifactor authentication
Security zones: Security zones group systems by trust: untrusted internet, screened subnet for public servers, trusted internal, restricted (payments, ICS). Lesson: Placement, zones, attack surface, connectivity
Segmentation: Segmentation splits the network into zones (VLANs, subnets, firewalls between them) so an attacker in one can't reach all. Lesson: Segmentation, access control, allow lists, isolation
Self-assessments: Self-assessments are reviews teams do of their own controls, often with a checklist, to find gaps before the auditors do. Lesson: Internal audits and assessments
Self-signed: A self-signed certificate is signed by its own key: fine for testing or internal use if you deploy trust yourself, but browsers warn because nothing they trust vouches for it. Lesson: CAs, third-party and self-signed
SELinux: SELinux (Security-Enhanced Linux) adds mandatory access control to Linux: policies limit what each process can touch, even if it runs as root. Lesson: Operating system security
Sensitive: Sensitive: could cause harm if exposed; needs protection (customer contact data). Lesson: Data classifications
Sensors: Sensors: collect traffic or event data from points in the network and feed the IDS or SIEM. Lesson: Network appliances
Server-side request forgery (SSRF): Forgery makes a server or browser send requests the user didn't intend: cross-site request forgery (CSRF) abuses a logged-in user's browser; server-side request forgery (SSRF) makes a server fetch internal resources. Lesson: Privilege escalation, forgery, directory traversal
Serverless: Serverless (function as a service): you upload code and the provider runs, scales and patches the servers you never see. Lesson: Serverless and microservices
Servers: Servers: minimal roles and services, patching, strong admin access, logging. Lesson: Hardening targets
Service disruption: Service disruption: taking services down. Lesson: Why they attack
Service provider: Supply chain vulnerabilities come from your providers: a service provider with weak security and access to you, a hardware provider shipping counterfeit or tampered parts, a software provider whose code or update… Lesson: Cloud-specific and supply chain
Service restart: Many changes need a service restart (for example restarting the web service so a new config loads) or an application restart. Lesson: Downtime and restarts
Session key: TLS uses this: asymmetric math to agree on a session key, then fast symmetric encryption for the data. Lesson: Key exchange
Session tokens: Browser-based: extensions, JavaScript, password managers, cookies and session tokens. Lesson: Vectors and attack surfaces added in V8
SHA-256: Use SHA-256 or stronger. Lesson: Hashing
Shadow AI: Shadow AI: unapproved AI tools used without IT review. Lesson: Poisoning, theft and leakage
Shadow IT: Shadow IT is staff using hardware, software or cloud services that IT hasn't approved, usually to get work done faster. Lesson: Insider threat and shadow IT
Shared responsibility model: Cloud-specific vulnerabilities come with cloud services: publicly exposed storage buckets, weak identity and access settings, insecure APIs, unprotected management consoles, and confusion over the shared… Lesson: Cloud-specific and supply chain
Side loading: Side loading is installing apps from outside the official app store (for example an APK from a website), which skips the store's security review. Lesson: Side loading and jailbreaking
SIEM: SIEM (security information and event management): aggregates and correlates logs, alerts and dashboards in one place. Lesson: Monitoring tools, part 1
Signatures: Signatures match known attack patterns: precise and low noise, but blind to new attacks. Lesson: IDS/IPS: signatures and trends
Simulation: Simulation: a realistic practice event (for example a simulated attack or outage) that people respond to. Lesson: Testing the plan
Single loss expectancy (SLE): Single loss expectancy (SLE) = asset value x EF. Lesson: The money formulas
Single point of failure: Automation has costs too: complexity (more moving parts to understand), cost (tools, development time), a single point of failure (if the automation platform breaks, everything it does stops), technical debt (quick… Lesson: Other considerations
Single sign-on (SSO): Single sign-on (SSO) means one login unlocks many apps. Lesson: Federation, SSO and interoperability
Site survey: Before installing access points, do a site survey: walk the building, measure signal and interference, and find where APs should go. Lesson: Wireless installation: site surveys and heat maps
Situational awareness: Situational awareness: noticing what is around you (tailgaters, shoulder surfers). Lesson: User guidance and training topics
Skimming: Objective 2.5 adds quishing (QR phishing), deepfake impersonation, skimming and forced entry, forgery attacks such as SSRF, and credential attacks like user enumeration and MFA bypass (push fatigue, stolen session… Lesson: New attacks and indicators of compromise
SLA: SLA (service-level agreement): measurable service levels (uptime 99.9%, response within 1 hour) and penalties. Lesson: Agreement types
SLO: SLA is the agreement; an SLO is one measurable target inside it. Lesson: Program management additions
Smishing: Smishing is SMS phishing by text message. Lesson: Phishing, vishing, smishing
SMS: Message-based vectors: email (phishing links and attachments), SMS text messages and instant messaging (IM) in chat apps. Lesson: Message-based, image-based, file-based
Snapshots: Snapshots: point-in-time copies of a VM or volume, quick to take and roll back. Lesson: Backups
SNMP traps: SNMP traps: a device sends an unrequested alert to the management station (UDP 162) when something happens. Lesson: Monitoring tools, part 2
Social engineering: Social engineering: pretexting, vishing, smishing, impersonation. Lesson: User guidance and training topics
Software development lifecycle (SDLC): Software development lifecycle (SDLC) policy: security built into every phase of building software. Lesson: Policies
Software provider: Supply chain vulnerabilities come from your providers: a service provider with weak security and access to you, a hardware provider shipping counterfeit or tampered parts, a software provider whose code or update… Lesson: Cloud-specific and supply chain
Software-defined networking (SDN): Software-defined networking (SDN) splits the network into a data plane (forwards packets), a control plane (decides where traffic goes) and a management plane (configure and monitor), all run from software. Lesson: Physical isolation, logical segmentation, SDN
Something you are: MFA combines factors from different categories: something you know (password, PIN), something you have (phone, token, smart card), something you are (biometrics: fingerprint, face) and somewhere you are (location,… Lesson: Multifactor authentication
Something you have: MFA combines factors from different categories: something you know (password, PIN), something you have (phone, token, smart card), something you are (biometrics: fingerprint, face) and somewhere you are (location,… Lesson: Multifactor authentication
Something you know: MFA combines factors from different categories: something you know (password, PIN), something you have (phone, token, smart card), something you are (biometrics: fingerprint, face) and somewhere you are (location,… Lesson: Multifactor authentication
Somewhere you are: MFA combines factors from different categories: something you know (password, PIN), something you have (phone, token, smart card), something you are (biometrics: fingerprint, face) and somewhere you are (location,… Lesson: Multifactor authentication
Spear phishing: Phishing uses fraudulent messages, usually email, to trick people into clicking, opening or revealing information; spear phishing targets specific people. Lesson: Phishing, vishing, smishing
SPF: SPF (Sender Policy Framework): a DNS TXT record listing which servers may send mail for the domain. Lesson: Email security
Spraying: Spraying tries one or a few common passwords against many accounts, staying under each account's lockout limit. Lesson: Password spraying and brute force
Spyware: Spyware secretly watches the user (browsing, screenshots, location) and sends the data out. Lesson: Spyware, keylogger, bloatware
SSE (Security Service Edge): SSE (Security Service Edge): cloud web gateway, CASB and ZTNA; SASE without the SD-WAN part. Lesson: Architecture and operations tools
Stakeholders: Stakeholders are everyone affected (other departments, customers, management), so they are consulted and told about timing. Lesson: Approval, ownership, stakeholders
Standard infrastructure configurations: Why automate: efficiency/time saving; enforcing baselines and standard infrastructure configurations (no drift, no typos); scaling in a secure manner (100 servers built as safely as one); employee retention (fewer… Lesson: Benefits
Standard operating procedure (SOP): A standard operating procedure (SOP) documents the step-by-step way routine changes are done, so they are done the same safe way every time. Lesson: Backout plan, maintenance window, SOP
Standards: Standards are mandatory, specific requirements that support a policy: password standards (length, MFA), access control standards, physical security standards (badges, locks), encryption standards (AES-256, TLS 1.2+). Lesson: Standards, procedures, guidelines
Static analysis: For applications: static analysis reviews source code without running it; dynamic analysis tests the running app (including fuzzing with unexpected input); package monitoring tracks the third-party libraries and… Lesson: Vulnerability scans and application testing
Static code analysis: Static code analysis (SAST): scans source code without running it. Lesson: Application security
Steganography: Steganography hides data inside other data, the cover (cover text/image): a message inside the pixels of a photo, an audio file, a video, or packet fields. Lesson: Steganography
Stored: Reflected (non-persistent) XSS bounces script in a crafted link off the server; stored (persistent) XSS saves it in the site, such as a product review, to hit everyone who views it. Lesson: Cross-site scripting (XSS)
Structured Query Language injection (SQLi): Structured Query Language injection (SQLi) happens when an app puts user input directly into a database query. Lesson: SQL injection (SQLi)
subject/system: A subject/system is the user, device or application asking for access. Lesson: Subjects, zones and the PEP
Supplicant: Three roles: the supplicant (the client), the authenticator (the switch or access point) and the authentication server (usually RADIUS). Lesson: Port security: 802.1X and EAP
Suppliers: Suppliers provide components and services that could be counterfeit or compromised before they reach you. Lesson: Supply chain
Supply chain: The supply chain vector attacks you through someone you trust. Lesson: Supply chain
Supply chain analysis: Supply chain analysis: look at the vendor's own suppliers and components, since their risk flows to you. Lesson: Vendor assessment
Switches: Switches and routers: change default creds, disable unused ports and services, SSH not Telnet, secure management access. Lesson: Hardening targets
Symmetric encryption: Symmetric encryption uses one shared secret key to encrypt and decrypt. Lesson: Symmetric encryption
system/process audit: A system/process audit reviews how systems and processes are configured and run against requirements, finding weaknesses scans miss (like no review of admin accounts). Lesson: Pen tests, disclosure programs and audits
Systems: Three layers of computing resources: Systems (servers, workstations: CPU, logins, processes), Applications (errors, failed logins, unusual transactions in the shop app) and Infrastructure (network devices, firewalls,… Lesson: What we monitor
T
Tabletop exercise: Tabletop exercise: people talk through a scenario around a table. Lesson: Testing the plan
Tap/monitor: Tap/monitor devices get a copy of traffic from a network tap or a switch port mirror (SPAN), so they can never block it (an IDS). Lesson: Device attributes: active/passive, inline/tap
Targeted: Awareness (5.6): an LMS to deliver and track training, targeted and corrective training, personnel behavior risk scoring. Lesson: Program management additions
Technical + corrective: Backups that recover data are technical + corrective. Lesson: One control, two labels
Technical + preventive: A firewall rule is technical + preventive. Lesson: One control, two labels
Technical controls: Technical controls are enforced by hardware or software: firewall rules, encryption, antivirus, an MFA prompt, OS login rules. Lesson: Technical and managerial
Technical debt: Automation has costs too: complexity (more moving parts to understand), cost (tools, development time), a single point of failure (if the automation platform breaks, everything it does stops), technical debt (quick… Lesson: Other considerations
Technology: Capacity planning makes sure there is enough of three things when demand jumps or a site fails: people (enough trained staff, cross-training), technology (servers, licenses, app capacity) and infrastructure (power,… Lesson: Continuity of operations and capacity planning
Test results: Test results come from trying the change first in a sandbox or test environment that mirrors production, so problems show up there, not in front of customers. Lesson: Impact analysis and test results
Testing: Testing proves the plan works: a tabletop exercise walks the team through a scenario in discussion, with no systems touched; a simulation acts out a realistic incident (for example a fake phishing attack or a staged… Lesson: Training and testing
Third-party: A third-party (public) CA is already trusted by browsers and operating systems, so use it for public sites like the online shop. Lesson: CAs, third-party and self-signed
Third-party vendors: Third-party vendors (the provider, integrators, marketplace add-ons) bring their own risk, so you vet them, write it into contracts and keep monitoring them. Lesson: Hybrid considerations and third-party vendors
Threat feed: A threat feed delivers current indicators and vulnerability news. Lesson: Threat feeds
Threat feeds: Threats come from threat feeds and intelligence sources (OSINT, ISACs, government and commercial feeds), are ranked by likelihood and impact, and follow an intelligence life cycle. Lesson: Objective 2.1: threat and vulnerability characteristics
Threat hunting: Threat hunting is proactive: analysts search for signs of attackers that no alert has flagged yet, guided by threat intelligence and hypotheses. Lesson: Root cause analysis and threat hunting
Threat scope reduction: Threat scope reduction shrinks the attack surface by limiting entry points and giving least-privilege, per-resource access. Lesson: Control plane ideas
Threat vector: A threat vector is the path an attacker uses to get in (email, a USB stick, an open port). Lesson: Vectors vs. attack surface
Ticket creation: Ticket creation and escalation: open a ticket from an alert and escalate it if nobody acts in time. Lesson: Use cases of automation and scripting
Time-based: Identity (4.5) adds identity proofing before accounts are issued, emergency access (break-glass) accounts, backup codes, passkeys (phishing-resistant FIDO2 keys), time-based access and compromised credential monitoring. Lesson: Identity, automation and AI in operations
Time-of-check (TOC): The classic is time-of-check to time-of-use (TOCTOU): the program checks something at time-of-check (TOC) and acts on it later at time-of-use (TOU); an attacker changes the thing in between. Lesson: Race conditions: TOC/TOU
Time-of-check to time-of-use (TOCTOU): The classic is time-of-check to time-of-use (TOCTOU): the program checks something at time-of-check (TOC) and acts on it later at time-of-use (TOU); an attacker changes the thing in between. Lesson: Race conditions: TOC/TOU
Time-of-day restrictions: Time-of-day restrictions: access only in allowed hours. Lesson: Access control models
Time-of-use (TOU): The classic is time-of-check to time-of-use (TOCTOU): the program checks something at time-of-check (TOC) and acts on it later at time-of-use (TOU); an attacker changes the thing in between. Lesson: Race conditions: TOC/TOU
Timestamps: New indicators include log manipulation (a cleared audit log), plaintext strings in malware, file system artifacts and altered timestamps. Lesson: New attacks and indicators of compromise
TLS: TLS VPNs run over port 443 and often work from a browser or light client. Lesson: VPN, remote access and tunneling
Tokenization: Tokenization replaces sensitive data with a random token that has no mathematical relationship to the original; only a protected token vault can map it back. Lesson: Tokenization and data masking
Trade secret: Trade secret: valuable because it is secret (the Kibble Krunch recipe). Lesson: Data types
Training: Training makes sure everyone knows their role in the plan before an incident. Lesson: Training and testing
Transfer: Transfer: shift the financial impact to someone else (insurance, outsourcing with contract terms). Lesson: Risk management strategies
Transport encryption: Transport encryption protects data in transit across a network: HTTPS (TLS) for web traffic, a VPN tunnel (IPsec or TLS-based) between sites or for remote users, SSH instead of Telnet, SFTP instead of FTP. Lesson: Transport/communication encryption
Transport method: Transport method: make sure the data is actually protected in transit, by the protocol itself (TLS) or a tunnel (VPN, IPSec). Lesson: Implementation of secure protocols
Transport mode: Tunnel mode encrypts the whole original packet (site-to-site); transport mode protects only the payload (host to host). Lesson: VPN, remote access and tunneling
Trends: Trends (anomaly or behavior-based detection) learn what normal traffic looks like and flag deviations, so they can catch new attacks but raise more false positives. Lesson: IDS/IPS: signatures and trends
Trojan: A Trojan pretends to be useful software (a free game, a "codec", a cracked app) but carries a hidden malicious payload, often a remote access Trojan (RAT) backdoor. Lesson: Trojan and ransomware
Trusted Platform Module (TPM): A Trusted Platform Module (TPM) is a security chip (or firmware) in a computer: it generates and stores keys, has a random number generator, holds unique keys burned in at manufacture, stores boot measurements for… Lesson: TPM and HSM
Tunnel mode: Tunnel mode encrypts the whole original packet (site-to-site); transport mode protects only the payload (host to host). Lesson: VPN, remote access and tunneling
two-person integrity/control: A security guard can make judgment calls, check IDs and respond; two-person integrity/control means two guards are needed so no one person can be compromised. Lesson: Eyes and IDs: video, guards, badges, lighting
Type: The type says what job it does: preventive, deterrent, detective, corrective, compensating or directive. Lesson: What a security control is
Typosquatting: Typosquatting registers misspelled lookalike domains (kibbelco.example, kibbleco-shop.example) to catch typos or fool readers. Lesson: Watering hole, brand impersonation, typosquatting
U
Ultrasonic: Ultrasonic sensors send high-frequency sound and measure the echo, used for motion and collision detection. Lesson: Sensors
Unexpected: Unexpected: things that do not fit (a coworker logging in at 3 a.m., a "vendor" asking for the server room). Lesson: Anomalous behavior recognition
Unintentional: Unintentional: honest mistakes (emailing the wrong person, a misconfigured share). Lesson: Anomalous behavior recognition
Unknown environment: Unknown environment (black box): no details; testers start like an outside attacker. Lesson: How much the testers know
Unsafe exception handling: New surfaces (2.4): hardcoded secrets, unsafe exception handling, stale credentials, rogue devices, LLMs, identity providers, public repositories and public object storage. Lesson: Vectors and attack surfaces added in V8
Unsecure networks: Unsecure networks: wireless (open Wi-Fi, old WEP/WPA, rogue access points), wired (open network jacks with no 802.1X or port security, so anyone can plug in), and Bluetooth (devices left discoverable, flaws in… Lesson: Unsupported systems and unsecure networks
Unskilled attacker: An unskilled attacker (once called a script kiddie) runs tools and scripts others wrote, without deep understanding; low sophistication and little funding, often motivated by curiosity, fame or causing chaos. Lesson: Hacktivist and unskilled attacker
Updating diagrams: After a change, updating diagrams (network maps, data flows) and updating policies/procedures keeps documentation true. Lesson: Update the paperwork
updating policies/procedures: After a change, updating diagrams (network maps, data flows) and updating policies/procedures keeps documentation true. Lesson: Update the paperwork
UPS: A UPS (uninterruptible power supply) runs on batteries, giving clean power instantly for minutes: enough to ride out blips or shut down cleanly. Lesson: Power
URL hijacking: DNS attacks include DNS poisoning (false records cached, sending users to the attacker's IP), domain hijacking (taking control of the domain registration) and URL hijacking (lookalike domains). Lesson: DNS attacks and wireless attacks
URL scanning: URL scanning: checks each requested URL against threat data. Lesson: Web filtering
User behavior analytics: User behavior analytics (UBA): learns normal user behavior and flags anomalies like 3 a.m. Lesson: Endpoint and data capabilities
User enumeration: Objective 2.5 adds quishing (QR phishing), deepfake impersonation, skimming and forced entry, forgery attacks such as SSRF, and credential attacks like user enumeration and MFA bypass (push fatigue, stolen session… Lesson: New attacks and indicators of compromise
User provisioning: User provisioning and resource provisioning: create accounts and servers from templates, the same way every time. Lesson: Use cases of automation and scripting
UTM: UTM (unified threat management): one box (firewall, IPS, antivirus, web filter, VPN) for small sites. Lesson: Firewall types
V
Validation of remediation: Validation of remediation: rescanning to confirm the finding is gone, an audit to check the change was made correctly, and verification (testing directly, for example confirming the patched version is running). Lesson: Validation and reporting
Vendor monitoring: Vendor monitoring continues after signing (reviews, reports, breach news). Lesson: Vendor selection, questionnaires, monitoring, rules of engagement
Vendor registry: A vendor registry tracks every third party. Lesson: Program management additions
Vendors: Vendors sell you software and hardware that may carry flaws or tampering. Lesson: Supply chain
Verification: Validation of remediation: rescanning to confirm the finding is gone, an audit to check the change was made correctly, and verification (testing directly, for example confirming the patched version is running). Lesson: Validation and reporting
Verification processes: Verification processes (call-backs, code words) against deepfake requests. Lesson: Defenses
Version control: Version control tracks every version of code, configurations, scripts and documents: who changed what, when and why. Lesson: Version control
Vertical: Privilege escalation gains more rights than intended: vertical (user to admin) or horizontal (one user to another user's data). Lesson: Privilege escalation, forgery, directory traversal
Video surveillance: Video surveillance (CCTV) records and can detect motion or objects. Lesson: Eyes and IDs: video, guards, badges, lighting
Virtual machine (VM) escape: Virtual machine (VM) escape is breaking out of a guest VM to reach the hypervisor or other VMs on the same host, the most serious virtualization flaw because one compromised guest can own the whole host. Lesson: VM escape and resource reuse
Virtualization: Virtualization: a hypervisor runs many virtual machines, each with its own full guest OS. Lesson: Virtualization and containerization
Virus: A virus attaches to a file or program and needs a user to run it to spread (program, boot sector, script and macro viruses; fileless viruses live only in memory and use built-in tools like PowerShell). Lesson: Virus and worm
Vishing: Vishing is voice phishing over the phone. Lesson: Phishing, vishing, smishing
Voice call: Voice call vectors include vishing calls, caller ID spoofing, voicemail scams and automated robocalls. Lesson: Voice call and removable device
Volume: Volume encryption covers a logical volume or container, which can be a data volume separate from the OS. Lesson: Data at rest: from disk to record
VPN: A VPN builds an encrypted tunnel across an untrusted network. Lesson: VPN, remote access and tunneling
Vulnerability classification: Prioritize using: vulnerability classification (what kind of flaw and how severe), exposure factor (the percentage of the asset's value that would be lost if the flaw is exploited), environmental variables (is it… Lesson: Prioritize with context
Vulnerability scan: A vulnerability scan checks systems for known flaws, missing patches and bad settings. Lesson: Vulnerability scans and application testing
Vulnerability scanners: Vulnerability scanners: find missing patches and weak settings across systems. Lesson: Monitoring tools, part 2
Vulnerability scans: Vulnerability scans show which weaknesses an attacker could have used. Lesson: Other data sources
Vulnerable software: Vulnerable software is any software with flaws an attacker can exploit. Lesson: Vulnerable software: client-based vs. agentless
W
WAF: WAF (web application firewall): protects web apps by inspecting HTTP; blocks SQL injection and XSS. Lesson: Firewall types
War: War: military goals between nations. Lesson: Why they attack
Warm site: Warm site: hardware and connectivity ready, but data and apps must be loaded; ready in hours to days. Lesson: Site considerations
Watering hole: A watering hole attack compromises a website the targets already visit (like a pet-industry trade forum) and waits for them. Lesson: Watering hole, brand impersonation, typosquatting
Who or what enforces it?: Ask one question: who or what enforces it? A device or software: technical. Lesson: Memory trick: who enforces it?
Wi-Fi: Connection methods: Cellular (carrier network, bypasses company Wi-Fi controls), Wi-Fi (watch for rogue APs and evil twins), Bluetooth (turn off discoverable mode, pair only known devices). Lesson: Mobile solutions
Wildcard: A wildcard certificate like *.kibbleco.example covers any single-level name such as shop. Lesson: CSR generation and wildcards
Wired: Unsecure networks: wireless (open Wi-Fi, old WEP/WPA, rogue access points), wired (open network jacks with no 802.1X or port security, so anyone can plug in), and Bluetooth (devices left discoverable, flaws in… Lesson: Unsupported systems and unsecure networks
Wireless: Unsecure networks: wireless (open Wi-Fi, old WEP/WPA, rogue access points), wired (open network jacks with no 802.1X or port security, so anyone can plug in), and Bluetooth (devices left discoverable, flaws in… Lesson: Unsupported systems and unsecure networks
Wireless attacks: Wireless attacks include deauthentication floods that kick users off Wi-Fi (802.11w management frame protection helps), jamming of the radio frequencies, and evil twin or rogue access points that capture traffic. Lesson: DNS attacks and wireless attacks
WO/SOW: WO/SOW (work order/statement of work): the specific job, deliverables, timeline and cost under the MSA. Lesson: Agreement types
Workforce multiplier: Why automate: efficiency/time saving; enforcing baselines and standard infrastructure configurations (no drift, no typos); scaling in a secure manner (100 servers built as safely as one); employee retention (fewer… Lesson: Benefits
Workstations: Workstations: patches, EDR, no local admin, host firewall. Lesson: Hardening targets
Worm: A worm spreads by itself across the network by exploiting vulnerabilities, with no user action, so it can infect thousands of machines fast. Lesson: Virus and worm
WPA3: WPA3 replaces WPA2's pre-shared key exchange with SAE, which resists offline password guessing and gives forward secrecy; protected management frames are required. Lesson: Wireless security settings
Y
You: In every model, you still own your data, your user accounts and who gets access. Lesson: The responsibility matrix
Z
Zero Trust: Zero Trust drops the old idea that anything inside the network is safe. Lesson: Never trust, always verify
Zero-day: A zero-day vulnerability is one the vendor doesn't know about yet or hasn't patched, so defenders have had "zero days" to fix it. Lesson: Zero-day
Zero-day attack: A zero-day attack exploits such an unpatched flaw. Lesson: Zero-day

Acronyms

Acronym	Stands for	What it means
3DES	Triple Data Encryption Standard	DES run three times with different keys. Retired: too slow and too weak for new systems; use AES.
AAA	Authentication, Authorization, and Accounting	The security trio: prove who you are, decide what you may do, and log what you did.
ABAC	Attribute-based Access Control	Access decided by attributes of the user, resource and situation, such as department, data label and location.
ACL	Access Control List	An ordered list of allow and deny rules on a router, firewall or file, checked from the top down.
AES	Advanced Encryption Standard	The standard symmetric cipher today: one shared key (128, 192 or 256 bits) encrypts and decrypts data in 128-bit blocks.
AH	Authentication Header	IPsec protocol that proves packets are authentic and unchanged but does not encrypt them.
AI	Artificial Intelligence	Software that learns patterns from data to make predictions or generate text and images.
AIS	Automated Indicator Sharing	A free US government (CISA) service for swapping threat indicators machine-to-machine between organizations.
ALE	Annualized Loss Expectancy	The expected loss from one risk per year: single loss expectancy times how often it happens per year (SLE x ARO).
AML/CTF	Anti-money Laundering/Counter-terrorism Financing	Rules and training to spot and report money laundering or payments that fund terrorism.
AP	Access Point	A device that connects wireless clients to the wired network.
API	Application Programming Interface	A defined way for one program to ask another for data or actions, such as web requests that return JSON.
APK	Android Package Kit	The install file for an Android app. APKs from outside the Play Store (sideloading) can carry malware.
APT	Advanced Persistent Threat	A skilled, well-funded attacker (often state-backed) that gets in quietly and stays hidden for a long time.
ARO	Annualized Rate of Occurrence	How many times a year a given risk is expected to happen (0.5 means once every two years).
ARP	Address Resolution Protocol	Finds the MAC address that goes with an IPv4 address on the local network. Fake replies enable ARP poisoning.
ASLR	Address Space Layout Randomization	Loads programs and data at random memory addresses each time, so an exploit can't guess where to jump.
ATT&CK	Adversarial Tactics, Techniques, and Common Knowledge	MITRE's free catalog of real attackers' tactics and techniques, used to map and detect attacks.
AUP	Acceptable Use Policy	The rules users agree to about what they may and may not do on company devices and networks.
AV	Antivirus; also Asset Value	Antivirus software, which finds malware. In risk math, AV is also asset value: what the thing is worth (SLE = AV x EF).
BC	Business Continuity	Keeping the organization's key work going during a disruption.
BCP	Business Continuity Planning	Planning that keeps the business's critical work going during and after a disruption.
BEC	Business Email Compromise	A scam email that pretends to come from a boss or supplier to get a payment, gift cards or data.
BGP	Border Gateway Protocol	The routing protocol between autonomous systems that ties the internet together.
BIA	Business Impact Analysis	Works out which business functions matter most and what an outage costs; it sets targets like RTO and RPO.
BIMI	Brand Indicators for Message Identification	A DNS record that lets mail apps show a brand logo, only for domains enforcing DMARC.
BIOS	Basic Input/Output System	Older firmware that tests the hardware and starts the operating system. UEFI has replaced it on modern PCs.
BPA	Business Partners Agreement	An agreement between business partners that sets out each side's share, duties and decision rights.
BPDU	Bridge Protocol Data Unit	The messages switches trade for Spanning Tree. BPDU guard shuts an edge port that suddenly receives them.
BSSID	Basic Service Set Identifier	The MAC address of an access point's radio, identifying one cell (BSS) of a wireless network.
BYOD	Bring Your Own Device	Staff use their own phones and laptops for work, under company security rules.
CA	Certificate Authority	A trusted organization that checks identities and signs digital certificates.
CAB	Change Advisory Board	The group that reviews, approves and schedules changes to systems.
CAPTCHA	Completely Automated Public Turing test to tell Computers and Humans Apart	A test meant to tell people from bots. Fake CAPTCHAs are now used as lures.
CAR	Corrective Action Report	A report that records a problem's root cause and the fix that stops it happening again.
CASB	Cloud Access Security Broker	Sits between users and cloud apps to see which cloud services are used and enforce security policy on them.
CBC	Cipher Block Chaining	A block cipher mode that mixes each block with the previous encrypted block, so identical blocks encrypt differently.
CCMP	Counter Mode/CBC-MAC Protocol	The AES-based encryption and integrity protocol used by WPA2.
CCTV	Closed-circuit Television	Video cameras that record to a private system for watching and evidence.
CDN	Content Delivery Network	Servers spread around the world that cache a site's content close to users for speed and to soak up DDoS traffic.
CEO	Chief Executive Officer	The top executive of a company.
CER	Crossover Error Rate	The biometric setting where false accepts equal false rejects. The lower the CER, the more accurate the system.
CERT	Computer Emergency Response Team	A team that handles computer security incidents for an organization or a country.
CFO	Chief Financial Officer	The executive in charge of the company's money; a favorite name for attackers to fake in BEC emails.
CHAP	Challenge Handshake Authentication Protocol	Login by challenge and response: the password itself is never sent, only a hash of it mixed with a random challenge.
CI	Continuous Integration	Developers merge code often and every change is built and tested automatically.
CI/CD	Continuous Integration and Continuous Deployment	An automated pipeline that builds, tests and ships code; a good place for security checks.
CIA	Confidentiality, Integrity, Availability	The three goals of security: keep data secret (confidentiality), correct (integrity) and reachable (availability).
CIO	Chief Information Officer	The executive in charge of the organization's IT and its strategy.
CIRT	Computer Incident Response Team	A team that handles computer security incidents for an organization.
CIS	Center for Internet Security	A nonprofit that publishes free hardening guides (CIS Benchmarks) and the CIS Controls.
CISO	Chief Information Security Officer	The executive who leads the security program and answers for security risk.
COOP	Continuity of Operation Planning	A plan to keep essential (often government) functions running during an emergency, even from another site.
COPE	Corporate Owned, Personally Enabled	The company buys and owns the device but lets the employee use it personally too.
CPU	Central Processing Unit	The main processor chip that runs program instructions.
CRL	Certificate Revocation List	A list published by a certificate authority of certificates it has revoked before they expired.
CRM	Customer Relationship Management	Software that tracks customers, contacts, sales and support history.
CSIRT	Computer Security Incident Response Team	A team that handles computer security incidents: it investigates, contains and coordinates the response.
CSO	Chief Security Officer	The executive responsible for the organization's security.
CSP	Cloud Service Provider	A company that sells cloud services, such as AWS, Microsoft Azure or Google Cloud.
CSPM	Cloud Security Posture Management	A tool that keeps checking cloud settings for risky misconfigurations, like public storage.
CSR	Certificate Signing Request	A request sent to a certificate authority with your public key and identity details, asking it to issue a certificate.
CSRF	Cross-site Request Forgery	An attack that makes a logged-in user's browser send a request the user never meant to send.
CTO	Chief Technology Officer	The executive who sets the organization's technology direction.
CVE	Common Vulnerabilities and Exposures	A public list that gives each known vulnerability an ID, like CVE-2024-3094.
CVSS	Common Vulnerability Scoring System	A 0 to 10 score for how severe a vulnerability is (9.0 and up is critical).
CWE	Common Weakness Enumeration	A catalog of software and hardware weakness types, such as improper input validation.
CYOD	Choose Your Own Device	Employees pick their work device from a short list the company approves and manages.
DAC	Discretionary Access Control	The owner of a file or resource decides who gets access, like setting permissions on your own folder.
DAST	Dynamic Application Security Testing	Tests a running app from the outside by sending attacks to it, without looking at its code.
DBA	Database Administrator	The person who runs and looks after an organization's databases.
DDoS	Distributed Denial of Service	Floods a target from many machines at once (often a botnet) so real users can't reach it.
DEP	Data Execution Prevention	Marks memory that holds data as not runnable, so code injected there can't execute.
DES	Data Encryption Standard	An old symmetric cipher with a 56-bit key. Easily brute-forced today; replaced by AES.
DHCP	Dynamic Host Configuration Protocol	Hands devices an IP address, subnet mask, gateway and DNS server automatically (Discover, Offer, Request, Acknowledge).
DHE	Diffie-Hellman Ephemeral	Diffie-Hellman key exchange with fresh keys for every session, which gives forward secrecy.
DKIM	DomainKeys Identified Mail	Signs outgoing email so receiving servers can check, with a key in DNS, that it came from the domain unchanged.
DLL	Dynamic Link Library	A Windows file of shared code that programs load; attackers may plant or inject a malicious one.
DLP	Data Loss Prevention	Tools that find sensitive data and stop it leaving by email, upload, USB or print.
DMARC	Domain-based Message Authentication, Reporting, and Conformance	A DNS policy telling receivers what to do with mail that fails SPF and DKIM checks, and where to send reports.
DMZ	Demilitarized Zone	A separate network zone for public-facing servers, between the internet and the internal network. Also called a screened subnet.
DNS	Domain Name System	The internet's phone book: it turns names like example.com into IP addresses.
DNSSEC	Domain Name System Security Extensions	Adds digital signatures to DNS answers so resolvers can tell they are genuine. It does not encrypt them.
DoH	DNS over HTTPS	DNS lookups sent inside encrypted HTTPS on port 443, so they blend in with web traffic.
DoS	Denial of Service	An attack that overloads or crashes a service so legitimate users can't use it.
DPO	Data Protection Officer	The person who oversees how an organization protects personal data, a role required by GDPR in many cases.
DR	Disaster Recovery	Getting IT systems and data back after a disaster such as a fire, flood or ransomware.
DRP	Disaster Recovery Plan	The written, step-by-step plan for restoring IT systems and data after a disaster.
DSA	Digital Signature Algorithm	A US standard algorithm for creating and checking digital signatures.
DSS	Data Security Standard	The rules part of PCI DSS: the security requirements for businesses that handle payment cards.
EAP	Extensible Authentication Protocol	A framework of login methods (EAP-TLS, PEAP and others) used with 802.1X on Wi-Fi and wired ports.
ECB	Electronic Code Book	The simplest block cipher mode: each block is encrypted alone, so patterns in the data show through. Avoid it.
ECC	Elliptic Curve Cryptography	Public-key crypto based on elliptic curves: as strong as RSA with much smaller keys, good for phones and IoT.
ECDHE	Elliptic Curve Diffie-Hellman Ephemeral	Key exchange on elliptic curves with fresh keys each session: what modern TLS uses, giving forward secrecy.
ECDSA	Elliptic Curve Digital Signature Algorithm	A digital signature algorithm that uses elliptic curves, with small keys and fast signing.
EDR	Endpoint Detection and Response	Software on each endpoint that records activity, spots threats and can isolate the device or kill processes.
EF	Exposure Factor	The share of an asset's value lost in one incident, as a percentage (SLE = AV x EF).
EFS	Encrypting File System	A Windows feature (on NTFS) that encrypts individual files and folders for the user who owns them.
EOI	Expression of Interest	An early vendor-selection step where suppliers say they are interested and qualified.
EOL	End of Life	The vendor stops making or selling a product; patches and support end soon after.
EOSL	End of Service Life	The point when a vendor stops supporting a product: no patches, so it should be replaced or isolated.
ERP	Enterprise Resource Planning	Software that runs a company's core processes, such as finance, ordering, inventory and HR, in one system.
ESP	Encapsulating Security Payload	IPsec protocol that encrypts packets and also checks that they are authentic and unchanged.
EXIF	Exchangeable Image File Format	Hidden data inside photos: camera, date and often GPS location.
FACL	File System Access Control List	Extra Linux file permissions for named users and groups beyond owner, group and other (set with setfacl).
FAR	False Acceptance Rate	How often a biometric system lets in the wrong person. The more dangerous error.
FDE	Full Disk Encryption	Encrypts a whole drive, so data is unreadable without the key if the device is lost (BitLocker, FileVault).
FIDO2	Fast Identity Online 2	A standard for passwordless, phishing-resistant logins with security keys and passkeys.
FIM	File Integrity Monitoring	Watches important files and alerts when one changes, by comparing hashes to a known-good baseline.
FRR	False Rejection Rate	How often a biometric system turns away the right person. Annoying, but safer than a false accept.
FTP	File Transfer Protocol	Transfers files on ports 20 and 21 with no encryption; logins travel in clear text.
FTPS	File Transfer Protocol Secure (FTP over TLS)	FTP with TLS encryption added. Not the same thing as SFTP.
GBIC	Gigabit Interface Converter	A hot-swappable transceiver module that connects a switch port to fiber or copper.
GCM	Galois Counter Mode	A fast AES mode that encrypts and checks integrity in one pass; used in TLS and IPsec.
GCMP	Galois/Counter Mode Protocol	AES-GCM based Wi-Fi encryption; an option in WPA3 and required for its 192-bit Enterprise mode.
GDPR	General Data Protection Regulation	The EU law that protects the personal data of people in the EU, with heavy fines for breaking it.
gMSA	Group Managed Service Account	A Windows service account whose long password Active Directory rotates automatically.
GPO	Group Policy Object	A bundle of Windows settings pushed from Active Directory to users and computers.
GPS	Global Positioning System	Satellite system that tells a device where it is; used for maps, tracking and finding lost phones.
GPU	Graphics Processing Unit	The processor that draws graphics; also used for heavy parallel math like AI.
GRE	Generic Routing Encapsulation	Wraps one packet inside another to make a tunnel. It does not encrypt on its own.
GUI	Graphical User Interface	Windows, icons and menus you click, instead of typed commands.
HA	High Availability	A design with spare parts and automatic failover so a service stays up when something breaks.
HDD	Hard Disk Drive	A disk drive with spinning platters and a moving head: cheap per gigabyte, slower than an SSD.
HIDS	Host-based Intrusion Detection System	Software on one computer that watches its logs, files and activity for signs of attack and raises alerts.
HIPAA	Health Insurance Portability and Accountability Act	The US law that protects patients' health information (PHI).
HIPS	Host-based Intrusion Prevention System	Software on one computer that watches for attacks and blocks them there.
HMAC	Hash-based Message Authentication Code	A hash mixed with a secret key, proving a message is unchanged and came from someone who has the key.
HOTP	HMAC-based One-time Password	One-time codes made from a shared secret and a counter that goes up with each use.
HR	Human Resources	The department that hires people, onboards and offboards them, and keeps staff records.
HSM	Hardware Security Module	A tamper-resistant hardware device that creates, stores and uses crypto keys so they never leave it.
HTML	Hypertext Markup Language	The tag language web pages are written in.
HTTP	Hypertext Transfer Protocol	The protocol for web pages, port 80. Not encrypted.
HTTPS	Hypertext Transfer Protocol Secure	HTTP encrypted with TLS, port 443: the padlock in the browser.
HVAC	Heating, ventilation, and air conditioning	Heating, cooling and airflow; keeps server rooms in a safe temperature and humidity range.
IaaS	Infrastructure as a Service	Rent virtual servers, storage and networks from a cloud; you still manage the OS and everything above it.
IaC	Infrastructure as Code	Defining servers, networks and settings in code files so they are built the same way every time.
IAM	Identity and Access Management	Managing who people are and what they can access: accounts, logins, roles and permissions.
ICMP	Internet Control Message Protocol	Carries network errors and tests, such as ping (echo) and the messages traceroute relies on.
ICS	Industrial Control Systems	Computers that run physical processes in factories, utilities and pipelines.
ID	Identifier	A name or number that identifies something, like a user ID or badge ID.
IDF	Intermediate Distribution Frame	A wiring closet on a floor or wing that links desks to the main distribution frame (MDF).
IdP	Identity Provider	The service that checks your login and vouches for you to other apps, for single sign-on.
IDS	Intrusion Detection System	Watches traffic or activity for attacks and raises alerts, but does not block.
IEC	International Electrotechnical Commission	A standards body that publishes some standards jointly with ISO, such as ISO/IEC 27001.
IEEE	Institute of Electrical and Electronics Engineers	The body that writes networking standards such as 802.3 (Ethernet) and 802.11 (Wi-Fi).
IIS	Internet Information Services	Microsoft's web server for Windows.
IKE	Internet Key Exchange	Sets up IPsec: the two ends authenticate and agree on keys (UDP port 500).
IM	Instant Messaging	Chat apps for real-time text messages; also a path for phishing (smishing's cousin).
IMAP	Internet Message Access Protocol	Reads email while keeping it on the server, synced across devices. Port 143, or 993 with TLS.
IMAPS	Internet Message Access Protocol Secure	IMAP email over TLS, port 993.
IoC	Indicators of Compromise	Evidence that a system was breached, such as a known-bad file hash, IP address or domain.
IoT	Internet of Things	Everyday devices with network connections, such as cameras, thermostats and smart speakers.
IP	Internet Protocol	The protocol that addresses and routes packets between networks.
IPAM	Internet Protocol Address Management	Tracks a network's IP address space, DHCP and DNS, which helps find unknown devices.
IPFIX	Internet Protocol Flow Information Export	The IETF standard for flow records (based on NetFlow v9): who talked to whom, and how much.
IPS	Intrusion Prevention System	Sits in the traffic path, spots attacks and blocks them.
IPSec	Internet Protocol Security	A suite that encrypts and authenticates IP packets, used for VPNs (AH, ESP, and IKE to set up keys).
IR	Incident Response	Handling a security incident: prepare, detect, contain, remove the threat, recover and learn.
IRP	Incident Response Plan	The written plan for handling security incidents: who does what, when, and how.
ISAC	Information Sharing and Analysis Center	An industry group where members share threat intelligence, such as for finance or health care.
ISO	International Organization for Standardization	The international standards body behind standards such as ISO/IEC 27001 for security management.
ISP	Internet Service Provider	The company that connects you to the internet.
IT	Information Technology	Computers, networks and the people who run them.
IV	Initialization Vector	A random value used with a key so the same plaintext encrypts differently each time.
JIT	Just-in-Time	Admin rights granted only when needed and removed automatically afterwards.
JSON	JavaScript Object Notation	A simple text format for data, like {"name": "Ranger"}, used by most web APIs.
KDC	Key Distribution Center	The Kerberos server that checks logins and hands out tickets.
KEK	Key Encryption Key	A key whose only job is to encrypt (wrap) other keys.
KMS	Key Management System	A service that creates, stores, rotates and controls the use of encryption keys in one place.
KRI	Key Risk Indicator	A metric that warns a risk is growing, such as the number of unpatched servers.
L2TP	Layer 2 Tunneling Protocol	A VPN tunneling protocol with no encryption of its own, so it is usually paired with IPsec.
LAN	Local Area Network	The network in one building or site.
LDAP	Lightweight Directory Access Protocol	The protocol for reading and searching a directory such as Active Directory. Port 389; LDAPS uses 636.
LDAPS	Lightweight Directory Access Protocol Secure	LDAP protected with TLS (port 636), so directory logins and queries are encrypted.
LEAP	Lightweight Extensible Authentication Protocol	An old Cisco wireless login method that is easy to crack. Don't use it.
LLM	Large Language Model	An AI model trained on huge amounts of text that generates language, like a chatbot.
LMS	Learning Management System	Software that assigns, delivers and tracks training, such as security awareness courses.
LSASS	Local Security Authority Subsystem Service	The Windows process that handles logins and holds credentials in memory, a target for tools like Mimikatz.
LTE	Long-Term Evolution	The 4G cellular data standard.
MAC	Mandatory Access Control	The system decides access by labels and clearances (like Secret or Top Secret); users can't change it.
MAC (address)	Media Access Control	The 48-bit hardware address burned into a network interface, written like 00:1A:2B:3C:4D:5E.
MAC (code)	Message Authentication Code	A short tag made with a shared secret key that proves a message is authentic and unchanged.
MBR	Master Boot Record	The old partition style: up to 4 primary partitions and disks up to 2 TB; boot code sits in the first sector.
MD5	Message Digest 5	An old 128-bit hash. Broken for security, but still seen for quick file checks.
MDF	Main Distribution Frame	The main wiring room, where outside lines enter and the core equipment sits.
MDM	Mobile Device Management	Central control of phones and tablets: enforce passcodes, push apps and settings, and wipe lost devices.
MFA	Multifactor Authentication	Logging in with two or more different kinds of proof: something you know, have or are.
MIME	Multipurpose Internet Mail Extensions	The standard that lets email carry attachments, HTML and non-English text; also labels file types on the web.
MOA	Memorandum of Agreement	A written agreement on how two parties will work together toward a shared goal.
MOU	Memorandum of Understanding	A non-binding statement of shared intent between two parties.
MPLS	Multiprotocol Label Switching	Carrier WAN technology that forwards traffic by short labels instead of full IP lookups.
MSA	Master Service Agreement	A master contract with a provider that sets the terms for all future work orders.
MSCHAP	Microsoft Challenge Handshake Authentication Protocol	Microsoft's version of CHAP. Version 2 has known weaknesses and is crackable.
MSP	Managed Service Provider	An outside company that runs your IT for a monthly fee.
MSSP	Managed Security Service Provider	An outside company that runs security monitoring and response for you.
MTBF	Mean Time Between Failures	The average time a repairable device runs between failures.
MTTF	Mean Time to Failure	The average time a non-repairable part lasts before it fails.
MTTR	Mean Time to Repair (or Recover)	The average time it takes to fix something and get it working again.
MX	Mail Exchange	DNS record that names the mail server for a domain.
NAC	Network Access Control	Checks a device and its user before letting it on the network (is it patched, does it have antivirus?).
NAS	Network-attached Storage	A box on the network that shares files over SMB or NFS.
NAT	Network Address Translation	Swaps private internal IP addresses for a public one as traffic leaves the network.
NDA	Non-disclosure Agreement	A contract to keep confidential information secret.
NFC	Near Field Communication	Very short-range wireless (a few centimeters) used for tap-to-pay and pairing.
NGFW	Next-generation Firewall	A firewall that also knows applications and users and has an IPS built in.
NIC	Network Interface Card	The hardware that connects a computer to a network.
NIDS	Network-based Intrusion Detection System	A sensor that watches network traffic for attacks and raises alerts.
NIPS	Network-based Intrusion Prevention System	A device in the network path that spots attacks in the traffic and blocks them.
NIST	National Institute of Standards & Technology	The US agency that publishes security standards and guides, such as the Cybersecurity Framework and SP 800.
NOP	No Operation	A CPU instruction that does nothing; long runs of them (a NOP sled) appear in buffer overflow exploits.
NTFS	New Technology File System	The main Windows file system: permissions, encryption (EFS), compression and journaling.
NTLM	New Technology LAN Manager	An older Windows challenge-response login, weaker than Kerberos and open to pass-the-hash attacks.
NTP	Network Time Protocol	Keeps device clocks in sync over the network (UDP 123), which logs and Kerberos rely on.
NVD	National Vulnerability Database	The US NIST database that adds CVSS scores and details to published CVEs.
OAuth	Open Authorization	Lets an app act on your account elsewhere with a limited token, without seeing your password.
OCSP	Online Certificate Status Protocol	Asks a certificate authority in real time whether one certificate has been revoked.
OPSEC	Operations Security	Protecting small, harmless-looking details that together could help an attacker.
OS	Operating System	The core software that runs a computer, such as Windows, macOS, Linux, Android or iOS.
OSINT	Open-source Intelligence	Information gathered from public sources such as websites, social media and public records.
OT	Operational Technology	Hardware and software that run physical equipment, such as factory lines, power and building systems.
OTA	Over-the-air	Updates delivered wirelessly to phones, cars and IoT devices.
OTP	One-time Password	A code that works only once, from an app, token, text or backup list.
OVAL	Open Vulnerability Assessment Language	A standard language for describing how to check a system's state for vulnerabilities (part of SCAP).
P2P	Peer-to-Peer	Devices talk directly to each other with no central server, as in file sharing.
PA	Policy Administrator	In zero trust, carries out the policy engine's decision by telling the enforcement point to open or close the session.
PaaS	Platform as a Service	A cloud platform to run your code on; the provider manages the servers, OS and runtime.
PAC	Protected Access Credential	A shared secret EAP-FAST uses to build its protective tunnel without certificates.
PAM	Privileged Access Management	Controls and records admin accounts: passwords in a vault, access only when needed, sessions logged.
PAP	Password Authentication Protocol	A login protocol that sends the password in clear text. Insecure.
PBKDF2	Password-based Key Derivation Function 2	Turns a password into a key using a salt and many rounds of hashing, to slow down cracking.
PC	Personal Computer	A personal computer: a desktop or laptop.
PCAP	Packet Capture	A file of captured network packets, made by tools like tcpdump and opened in Wireshark.
PCI DSS	Payment Card Industry Data Security Standard	The security rules every business that takes payment cards must follow.
PDF	Portable Document Format	A file format that looks the same on every device; can hide malicious links or scripts.
PDU	Power Distribution Unit	A rack power strip that feeds equipment; smart ones can be monitored and switched remotely.
PE	Policy Engine	In zero trust, the part that decides whether to grant access, weighing policy, identity, device and risk.
PEAP	Protected Extensible Authentication Protocol	Wraps the Wi-Fi login in a TLS tunnel made with only a server certificate; users then log in with a password.
PEM	Privacy-enhanced Mail	A text format for certificates and keys, with -----BEGIN and -----END lines around Base64 data.
PEP	Policy Enforcement Point	In zero trust, the gate in the data path that allows or blocks the connection as instructed.
PFS	Perfect Forward Secrecy	Fresh session keys every time, so a stolen long-term key can't decrypt past sessions.
PFX	Personal Information Exchange	A password-protected file (PKCS #12) that bundles a certificate with its private key.
PGP	Pretty Good Privacy	Encrypts and signs email and files with public and private keys.
PHI	Protected Health Information	Health information tied to a person, protected by laws like HIPAA.
PII	Personally Identifiable Information	Information that identifies a person, such as name, address, Social Security number or birth date.
PIN	Personal Identification Number	A short secret number: something you know.
PIR	Post-incident Reporting	The formal report after an incident: timeline, impact, root cause and improvements.
PIV	Personal Identity Verification	The US federal smart card ID used for building access and computer login.
PKCS	Public Key Cryptography Standards	A family of public-key standards; for example, PKCS #12 is the format of .pfx files.
PKI	Public Key Infrastructure	The system of CAs, certificates and keys that lets strangers trust each other's identities online.
POP	Post Office Protocol	Downloads email to one device, usually removing it from the server. POP3 uses port 110, or 995 with TLS.
POS	Point of Sale	The checkout system, such as a register and card reader. PCI DSS covers it.
POTS	Plain Old Telephone Service	The old analog landline telephone network.
PPTP	Point-to-Point Tunneling Protocol	An old VPN protocol with broken security. Don't use it.
PSK	Pre-shared Key	A shared password everyone types to join a network, as in WPA2-Personal.
PTZ	Pan-tilt-zoom	A camera that can be turned (pan), tilted and zoomed remotely.
PUP	Potentially Unwanted Program	Software you didn't really want, like adware or toolbars bundled into an installer.
QR	Quick Response	A square barcode phones can scan; a fake one can lead to a phishing site (quishing).
RA	Registration Authority	Checks a person's or device's identity for a certificate authority before a certificate is issued.
RADIUS	Remote Authentication Dial-in User Service	A central login (AAA) service used by Wi-Fi, VPN and switches. UDP 1812 and 1813; only the password is encrypted.
RAID	Redundant Array of Inexpensive Disks	Combines several disks for speed, redundancy or both (RAID 0, 1, 5, 6, 10). Not a backup.
RAM	Random-Access Memory	Fast working memory that is wiped when the power goes off.
RAS	Remote Access Server	A server that lets remote users dial or connect in to the network.
RAT	Remote Access Trojan	Malware that gives an attacker remote control of a computer.
RBAC	Role-based Access Control	Access by job role: people get the permissions of the roles they hold.
RBAC (rule)	Rule-based Access Control	Access by rules the system checks, such as time of day or source address, for everyone.
RC4	Rivest Cipher version 4	An old stream cipher used by WEP and TKIP. Broken; don't use it.
RCE	Remote Code Execution	A flaw that lets an attacker run their own code on a system over the network. Usually critical.
RCS	Rich Communication Services	Modern phone messaging that replaces SMS with chat features like typing indicators and high-quality media.
RDP	Remote Desktop Protocol	Microsoft's remote desktop protocol, TCP port 3389. Don't expose it to the internet.
RF	Radio Frequency	Radio signals, such as Wi-Fi and Bluetooth.
RFC	Request for Comments	IETF documents that define Internet protocols and standards.
RFI	Request for Information	An early document asking vendors what they offer, before detailed requirements exist.
RFID	Radio Frequency Identification	Reads tags by radio without line of sight, as in badges, inventory tags and toll passes.
RFP	Request for Proposal	A document asking vendors for detailed proposals against defined requirements.
RFQ	Request for Quote	A document asking vendors to price clearly specified goods or services.
ROE	Rules of Engagement	What a penetration test may and may not do: targets, times, methods and contacts.
ROI	Return on Investment	What an investment returns compared to what it costs.
RPO	Recovery Point Objective	How much data, in time, you can afford to lose; it sets how often you back up.
RPS	Redundant Power Supply	A second power supply that keeps a device running if one supply or feed fails.
RSA	Rivest, Shamir, & Adleman	A public-key algorithm based on the difficulty of factoring large numbers; used for signatures and key exchange.
RTBH	Remotely Triggered Black Hole	Stops a DDoS by routing the attacked address's traffic into a black hole (null) upstream.
RTF	Rich Text Format	A document format that can carry embedded objects, sometimes used to deliver exploits.
RTO	Recovery Time Objective	How long a system can be down before the business is badly hurt; the target time to restore it.
RTOS	Real-time Operating System	An operating system that answers within strict, guaranteed time limits; found in embedded devices.
RTP	Real-time Transport Protocol	Carries real-time audio and video, as in VoIP calls, usually over UDP.
S/MIME	Secure/Multipurpose Internet Mail Extensions	Signs and encrypts email using certificates.
SaaS	Software as a Service	Finished software you use over the internet, like webmail; the provider runs everything.
SAE	Simultaneous Authentication of Equals	The WPA3 password handshake (Dragonfly), which stops offline password guessing.
SAML	Security Assertion Markup Language	XML messages an identity provider sends to web apps saying who you are, for single sign-on.
SAN (certificate)	Subject Alternative Name	A certificate field listing every name the certificate covers, such as example.com and www.example.com.
SAN (storage)	Storage Area Network	A dedicated network that gives servers block-level storage, as if the disks were local.
SASE	Secure Access Service Edge	Networking (SD-WAN) and security (SWG, CASB, ZTNA, firewall) delivered together from the cloud.
SAST	Static Application Security Testing	Scans source code for security flaws without running it.
SBOM	Software Bill of Materials	A list of every component and library inside a piece of software, to spot vulnerable ones quickly.
SCADA	Supervisory Control and Data Acquisition	Systems that monitor and control industrial processes, often spread over large areas like pipelines and grids.
SCAP	Security Content Automation Protocol	NIST standards for automatically checking systems for vulnerabilities and settings.
SCEP	Simple Certificate Enrollment Protocol	Lets devices request and receive certificates automatically, often through MDM.
SCIM	System for Cross-domain Identity Management	A standard for creating, changing and removing user accounts across apps automatically.
SD-WAN	Software-defined Wide Area Network	Manages WAN links between sites from one controller and picks the best path (broadband, LTE, MPLS) per app.
SDK	Software Development Kit	A set of tools, libraries and docs for building apps for a platform.
SDLC	Software Development Lifecycle	The stages of building software: plan, design, code, test, release and maintain.
SDN	Software-defined Networking	Network control moved into central software that programs the switches and routers.
SED	Self-encrypting Drives	A drive that encrypts everything written to it in its own hardware.
SELinux	Security-enhanced Linux	Linux mandatory access control: policy rules limit what each program can touch, even if it runs as root.
SFP	Small Form-factor Pluggable	A small hot-swappable transceiver for switch and router ports (fiber or copper).
SFTP	SSH File Transfer Protocol	File transfer through SSH on port 22, encrypted. Not the same as FTPS.
SHA	Secure Hash Algorithm	A family of hash functions; SHA-256 is common today, SHA-1 is broken.
SIEM	Security Information and Event Management	Collects logs from across the network in one place, links related events and raises alerts.
SIM	Subscriber Identity Module	The small card (or eSIM) that ties a phone to a cellular account and number.
SLA	Service-level Agreement	A contract's promised service level, such as 99.9% uptime or a 4-hour response.
SLE	Single Loss Expectancy	What one occurrence of a risk costs: asset value times exposure factor (AV x EF).
SMBv1	Server Message Block version 1	The original SMB file-sharing protocol: insecure (WannaCry spread through it). Turn it off.
SMS	Short Message Service	Plain text messages over the cellular network. Weak as a second login factor.
SMTP	Simple Mail Transfer Protocol	Sends email between mail servers (port 25) and from apps to their server (587).
SNMP	Simple Network Management Protocol	Lets a monitoring system read and change device settings and receive alerts (traps). UDP 161 and 162.
SNMPv1	Simple Network Management Protocol version 1	The first SNMP: community strings travel in clear text. Insecure.
SNMPv3	Simple Network Management Protocol version 3	The secure SNMP: user logins, integrity checks and encryption.
SOAP	Simple Object Access Protocol	An XML-based way for programs to call each other over the network.
SOAR	Security Orchestration, Automation, Response	Automates security response steps (playbooks) across tools, so routine alerts are handled fast.
SoC	System on Chip	A whole computer (CPU, graphics, memory controller and more) on one chip, as in phones.
SOC	Security Operations Center	The team, often 24/7, that watches for security events and responds to them.
SOP	Standard Operating Procedure	A written, step-by-step way to do a routine task the same way every time.
SOW	Statement of Work	Spells out the specific work, deliverables and deadlines for one project.
SOX	Sarbanes-Oxley Act	The US law that requires public companies to keep accurate financial records and controls.
SP	Service Provider; also Special Publication	In SAML, the app that trusts the identity provider. NIST also names its guides SP, like SP 800-88.
SPAN	Switched Port Analyzer	A switch feature that copies (mirrors) traffic from some ports to a monitoring port.
SPF	Sender Policy Framework	A DNS TXT record listing which servers may send email for a domain.
SPIM	Spam over Internet Messaging	Spam sent over instant messaging.
SQL	Structured Query Language	The language for querying and changing data in relational databases.
SQLi	SQL Injection	Typing database commands into an app's input so the database runs them. Stopped by parameterized queries.
SRTP	Secure Real-time Transport Protocol	Encrypted and authenticated RTP, for secure voice and video calls.
SSD	Solid-state Drive	Storage on flash chips, with no moving parts: much faster than a spinning hard drive.
SSE	Security Service Edge	Cloud-delivered security (web gateway, CASB, ZTNA): SASE without the SD-WAN part.
SSH	Secure Shell	An encrypted remote command line, TCP port 22. Replaces Telnet.
SSID	Service Set Identifier	The name of a Wi-Fi network.
SSL	Secure Sockets Layer	The old protocol that came before TLS. Every version is broken; "SSL certificates" today are really TLS.
SSN	Social Security Number	The US government ID number: highly sensitive PII.
SSO	Single Sign-on	Log in once and get into many apps without signing in again.
SSRF	Server-Side Request Forgery	Tricks a server into making requests for the attacker, often to internal systems or cloud metadata.
STIX	Structured Threat Information eXchange	A standard format for describing threat intelligence, such as indicators and attackers.
STP	Spanning Tree Protocol	Switches block redundant links so frames can't loop forever.
SVG	Scalable Vector Graphics	An image format made of text (XML); it can carry scripts, so it can be used to deliver attacks.
SWG	Secure Web Gateway	Filters users' web traffic, blocking malicious and banned sites wherever the users are.
TACACS+	Terminal Access Controller Access-Control System Plus	Cisco's central login (AAA) protocol over TCP 49: encrypts the whole message and controls each admin command.
TAXII	Trusted Automated eXchange of Indicator Information	A protocol for sharing threat intelligence (in STIX format) over HTTPS.
TCP	Transmission Control Protocol	Reliable, connection-based delivery: a three-way handshake, then data is acknowledged and resent if lost.
TCP/IP	Transmission Control Protocol/Internet Protocol	The family of protocols the internet runs on, named after its two best known.
TGT	Ticket Granting Ticket	The Kerberos ticket you get at login, used to ask for tickets to other services.
TKIP	Temporal Key Integrity Protocol	WPA's stopgap encryption, built on RC4. Deprecated and weak.
TLS	Transport Layer Security	Encrypts and authenticates connections, such as HTTPS. Use TLS 1.2 or 1.3.
TOC	Time-of-check	When a program checks something; if it acts later (time of use), an attacker may change it in between.
TOCTOU	Time-of-Check to Time-of-Use	A race condition: something is checked, then changed by an attacker before it is used.
TOTP	Time-based One-time Password	A login code made from a shared secret and the current time, changing about every 30 seconds.
TOU	Time-of-Use	When a program uses something it checked earlier; changing it in between is a TOCTOU race.
TPM	Trusted Platform Module	A security chip on the motherboard that stores keys and checks that the boot hasn't been tampered with.
TTL	Time to Live	In IP, a hop count each router lowers so lost packets die; in DNS, how long an answer may be cached.
TTP	Tactics, Techniques, and Procedures	How an attacker operates: their goals (tactics), methods (techniques) and step-by-step habits (procedures).
TXT	Text record	DNS record that holds text; SPF, DKIM, DMARC and domain checks are published this way.
UAT	User Acceptance Testing	Real users test the finished software to confirm it does what they need before it goes live.
UBA	User Behavior Analytics	Learns what normal activity looks like for each user and flags unusual behavior.
UDP	User Datagram Protocol	Fast, connectionless delivery with no handshake or resending; used for DNS, VoIP and streaming.
UEFI	Unified Extensible Firmware Interface	Modern PC firmware that replaced BIOS: GPT boot disks, Secure Boot and a graphical setup screen.
UEM	Unified Endpoint Management	One console to manage and secure all endpoints: phones, laptops, desktops and more.
UPS	Uninterruptible Power Supply	A battery that keeps equipment running through short outages and allows a safe shutdown.
URL	Uniform Resource Locator	A web address, like https://www.example.com/page.
USB	Universal Serial Bus	The common plug for keyboards, drives, phones and chargers.
UTM	Unified Threat Management	One box that combines firewall, IPS, antivirus, web filtering and more.
VBA	Visual Basic for Applications	The macro language inside Microsoft Office; a common way to hide malware in documents.
VDE	Virtual Desktop Environment	A desktop that runs on a server and is shown on your device over the network.
VDI	Virtual Desktop Infrastructure	Desktops that run as virtual machines in a data center and are reached over the network.
VLAN	Virtual Local Area Network	Splits one physical switch into separate logical networks.
VM	Virtual Machine	A software computer running on a hypervisor, with its own OS, sharing the real hardware.
VNC	Virtual Network Computing	A remote desktop-sharing system; exposing it to the internet invites attacks.
VoIP	Voice over IP	Phone calls carried over IP networks instead of phone lines.
VPC	Virtual Private Cloud	Your own isolated private network inside a public cloud.
VPN	Virtual Private Network	An encrypted tunnel across an untrusted network, such as the internet.
WAF	Web Application Firewall	A firewall for web apps: inspects HTTP traffic and blocks attacks like SQL injection and XSS.
WAN	Wide Area Network	A network that links sites across long distances.
WAP	Wireless Access Point	A device that connects wireless clients to the wired network.
WEP	Wired Equivalent Privacy	The original Wi-Fi encryption, broken within minutes. Never use it.
WIDS	Wireless Intrusion Detection System	Watches the airwaves for rogue access points and wireless attacks, and alerts.
WIPS	Wireless Intrusion Prevention System	Watches the airwaves for rogue access points and wireless attacks, and blocks them.
WPA	Wi-Fi Protected Access	Wi-Fi Protected Access: the original version used TKIP and is outdated.
WPA2	Wi-Fi Protected Access 2	Wi-Fi security with AES (CCMP). Personal mode uses a shared password; Enterprise uses 802.1X logins.
WPA3	Wi-Fi Protected Access 3	The newest Wi-Fi security: SAE stops offline password guessing, with stronger encryption options.
WPS	Wi-Fi Protected Setup	Push-button or PIN Wi-Fi setup. The PIN can be brute-forced, so turn it off.
XCCDF	Extensible Configuration Checklist Description Format	The SCAP format for security checklists, such as hardening benchmarks.
XDR	Extended Detection and Response	Detection and response that pulls together data from endpoints, network, cloud and email.
XML	Extensible Markup Language	A text format that marks up data with tags; used by SAML and SOAP.
XOR	Exclusive Or	A bit operation that is 1 when the inputs differ; a building block of ciphers.
XSRF	Cross-site Request Forgery	Another name for CSRF: tricks a logged-in browser into sending a request the user never meant.
XSS	Cross-site Scripting	Injecting script into a website so it runs in other visitors' browsers.
ZTNA	Zero Trust Network Access	Gives users access to one app at a time after checking who and what they are, instead of whole-network VPN access.

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