AP® Cybersecurity glossary
Key terms, unit by unit
Every term is defined in the words the course and exam description (CED) uses, tagged with the units it appears in, and linked to the lesson that teaches it.
A
- Acceptance
A risk strategy: a deliberate decision to live with the residual risk, because absolute security is unattainable.
- Access control list (ACL)
The ordered set of rules a firewall uses to permit or deny inbound and outbound traffic; the first matching rule is executed.
- Access control vestibule
A small entry space with two doors that lets one authorized person through at a time, so nobody can be admitted with them.
- Address resolution protocol (ARP)
The protocol that finds the media access control (MAC) address belonging to an internet protocol (IP) address on the same local area network (LAN), and stores the pair in an ARP table.
- Adversary
A person or group trying to compromise a system. College Board says adversary, not "hacker".
- Alert fatigue
When responders get used to false positives and take alerts less seriously, assuming they are false before investigating.
- Anomaly-based detection
Detection that compares data to a baseline of normal activity and alerts on data outside a tolerance range; catches new attacks but costs more and has more false positives.
- ARP poisoning
Sending falsified address resolution protocol (ARP) packets so a device's ARP table pairs the target's internet protocol (IP) address with the adversary's media access control (MAC) address.
- Artificial intelligence (AI)
Computer systems that perform tasks such as generating text, recognizing patterns or sorting events, used by both adversaries and defenders.
- Asset
Anything valuable: financial resources, intellectual property, data, digital infrastructure, physical property or reputation.
- Authority
A social engineering tactic: impersonating someone with power over the target, or relaying "their" instructions.
- Availability
A security principle: data and services are accessible to authorized people when needed. Without it: unexpected downtime.
- Avoidance
A risk strategy: stop the activity that creates the risk; impossible if the activity is critical to the mission.
B
- Beacon frame
A frame a wireless access point broadcasts several times a second to announce its service set identifier (SSID) and wireless encryption protocols.
- Bollard
A short, sturdy post that stops vehicles from reaching a building entrance or area.
- Broadcast address
The highest address of a network, such as 192.168.1.255; a packet sent to it is delivered to every device on that network.
C
- Card cloning
A physical attack where the adversary copies an authorized user's access card to gain everything that user can access.
- Challenge questions
Personal questions a website uses to verify identity, such as a pet's name or a birthdate.
- Command and control (C2)
A way for adversaries to send commands to a compromised device and receive its output.
- Confidentiality
A security principle: only authorized people, systems or processes can access data. Without it: data theft or destruction.
- Consensus
A social engineering tactic that creates social pressure by making the target believe everyone else is already doing it.
- Corrective control
A security control function that fixes problems and restores systems, such as patching, repairing a card reader or an intrusion prevention system (IPS).
- Cost-effective
A control that costs less to install and maintain than the expected loss from the attack it prevents.
- Credential harvesting
Collecting real usernames and passwords through a fake login site.
- Cyberterrorist
An adversary motivated by politics or beliefs who disrupts entire communities, regions or nations, such as a power grid or water plant.
D
- Data in transit
Data moving across a network, as opposed to data at rest, which is stored on a drive.
- Default gateway
The address of the router on a host's own network, to which the host sends every packet addressed to another network.
- Defense in depth
A strategy that uses multiple types of security controls in layers, so if one is bypassed another still protects the asset.
- Denial of service (DoS)
An attack that makes a system or resource unavailable to authorized users.
- Detection rule
A rule an automated detection system uses to flag likely malicious activity, which AI can suggest and a detection engineer should review.
- Detective control
A security control function that identifies attacks as they happen, such as cameras, intrusion detection systems (IDSs) and security information and event management (SIEM) systems.
- Digital avatar
An AI-made copy of a person's voice or image, built from existing samples, used to impersonate them on calls or video.
- Distributed denial of service (DDoS)
A denial of service attack in which many devices attack the same target at the same time.
- DNS poisoning
Planting a fake domain name system (DNS) record on a DNS server so users are redirected, typically to a malicious website.
- Domain name system (DNS)
The system that translates domain names into internet protocol (IP) addresses, using DNS servers, authoritative name servers and DNS records.
- Dumpster diving
A physical attack where the adversary searches a target's trash for information that helps them reach their goal.
E
- Eavesdropping
Capturing data in transit in order to read, record or copy it.
- Elicitation
Getting a target to reveal sensitive information through conversation or messages, a goal of social engineering.
- Escalate privileges
To reach accounts with more permissions, the goal of the lateral movement phase.
- Evil twin
An adversary's access point that copies or imitates a legitimate network's service set identifier (SSID) so users join it by mistake.
- Exfiltrate
To send stolen data out of an organization, part of the taking action phase.
- Extensible authentication protocol (EAP)
A framework that lets users authenticate to a wireless network through an approved authentication server, required by many wireless security policies.
F
- False negative
When an adversary bypasses a detection system, so a real attack raises no alert.
- False positive
An alert for activity that is actually harmless; high rates waste time and cause alert fatigue.
- Familiarity
A social engineering tactic: pretending to be, or to know, someone close to the target to build trust.
- Firewall
Software that allows or denies network traffic in or out of a network using a set of rules called an access control list (ACL); it runs on its own device or inside another one, such as a router.
- Foothold
A first point of access on a target's computer, gained during the initial access phase.
- Frame
A unit that wraps a packet for one link, with the media access control (MAC) addresses of the two devices on that link.
H
- Hacktivist
An adversary who compromises computers and networks to support a social, political or personal cause, believing the goal justifies illegal methods.
- Host
A device that sends or receives data on a network, such as a laptop, phone, printer or server.
- Hybrid detection
Detection that combines signature-based and anomaly-based methods; the most expensive option and it generates more alerts.
I
- Incident response plan (IRP)
A managerial control that sets out the steps an organization follows when an attack happens.
- Indicator of compromise (IoC)
Evidence in data or traffic that a system may be under attack, such as connections to known malicious addresses or mismatched port and application traffic.
- Insider adversary
An adversary who already has legitimate credentials and access to systems and data, sometimes recruited by outsiders, often motivated by greed or revenge.
- Integrity
A security principle: data are accurate and trustworthy. Without it: data manipulation.
- Internet control message protocol (ICMP)
A protocol for short test and error messages between devices, used by ping; it has no port numbers.
- Intimidation
A social engineering tactic where the adversary threatens negative consequences if the target does not comply.
- IP address
A numerical identifier assigned to a device's connection by the network it joins, made of a network portion and a host portion.
J
- Jamming
Broadcasting radio noise so wireless devices cannot communicate: an attack on availability.
K
- Keylogger
A device or program that records every key a user types, which can capture passwords and messages.
L
- Large language model (LLM)
A generative AI model trained on huge text data sets that writes human-like text, and can leak or repeat what it learned.
- Lateral movement
Using access to one compromised device to compromise other devices on the same local area network (LAN).
- Likelihood and severity
The two factors of a risk assessment: how probable an attack is, and how bad the damage would be.
- Local area network (LAN)
A network that covers one building or site and is controlled by one organization or household.
- Low-skilled and high-skilled adversaries
Low-skilled adversaries use malicious tools made by others against known vulnerabilities; high-skilled adversaries build or adapt tools and find zero days.
M
- MAC address
A 48-bit identifier of a network interface card, written in hexadecimal and used to deliver frames on one local link.
- MAC filtering
Allowing only devices with approved media access control (MAC) addresses to join a network or use a switch port.
- MAC flooding
Sending a switch many frames with different fake media access control (MAC) addresses so its table fills and it broadcasts frames out of every port.
- MAC spoofing
Making a device send a media access control (MAC) address other than its own.
- Malware
Software designed to harm a device or its user, such as by stealing data, spying or giving an adversary control.
- Managerial control
A security control type made of rules, guidelines, policies and procedures, such as password policies, access reviews and incident response plans.
- Mitigation
A risk strategy: add security controls to reduce the likelihood or impact of a risk.
- Motion sensor
A detective control that alerts security to movement, best placed where traffic is unexpected and paired with cameras.
- Multifactor authentication (MFA)
A login that requires extra proof of identity, such as a one-time code, in addition to a password.
N
- Network data port
A socket in a wall that is cabled to a switch port; plugging a device into it connects that device to the local area network (LAN).
- Network intrusion detection system (NIDS)
An automated tool that analyzes network data to determine if malicious activity is happening and generates an alert.
- Network intrusion prevention system (NIPS)
An automated tool that detects malicious network activity like an IDS and can also halt it by closing ports, blocking addresses or rejecting protocols.
- Network segmentation
Dividing a network into smaller, isolated segments or subnets so attacks are contained and each segment can have its own security level.
- Next-generation firewall (NGFW)
A firewall with stateless and stateful filtering plus advanced features such as intrusion prevention, deep packet inspection and filtering by application type.
O
- On-path attack
An attack in which the adversary secretly sits between two parties, capturing and possibly altering the data they exchange.
- One-time password (OTP)
A code that works for a single login or a short time, often sent by text or an authenticator app as a second factor.
- Online password attack
An attack where an adversary tries to log in to a device or service using common passwords, common patterns or stolen passwords.
- Open source intelligence (OSINT)
Freely available information, such as social media, websites and public records, used during reconnaissance.
P
- Packet
A small unit of data sent across a network, made of headers (addresses and control information) and a payload (the data).
- Passphrase
A long password made of several words, easier to remember than random characters and hard to guess when the words are unrelated.
- Password dictionary
A list of likely passwords built from personal information about a target, submitted by an automated tool.
- Password manager
A tool that generates and stores long, random, unique passwords so each account can have its own.
- Persistence
The attack phase where adversaries keep access without breaking in again, often with command and control through a RAT or rootkit.
- Phishing
A social engineering message, usually an email or text, that pretends to be trustworthy to get the target to reveal information, click a link or open a file.
- Physical control
A security control type for the physical space, such as locks, fences, cameras, bollards and guards.
- Piggybacking
A physical attack where the adversary uses social engineering to get an authorized person to let them into a restricted area.
- Port security
A switch feature that limits how many media access control (MAC) addresses can be assigned to a single switch port.
- Pretexting
A social engineering tactic where the adversary creates a believable reason to contact the target.
- Preventative control
A security control function that stops an attack before it happens, such as locks and encryption.
Q
- Qualitative and quantitative risk assessment
Two kinds of risk result: quantitative gives a number or money value; qualitative gives a descriptive label.
R
- Reconnaissance
The first phase of a cyberattack, gathering as much information about a target as possible, often from open source intelligence.
- Remote access trojan (RAT) and rootkit
Malware that keeps an adversary's access to a device; a RAT gives remote control, a rootkit hides deep in the system.
- Residual risk
The risk that remains after an organization has avoided, transferred and mitigated what it can; the level it chooses to accept.
- Risk
The chance that a threat exploits a vulnerability to compromise an asset, assessed by likelihood and severity.
- Rogue access point
An unauthorized wireless access point connected to an organization's network, often through an open data port.
- Router
A device that joins networks and forwards packets between them by reading internet protocol (IP) addresses.
- Router security policy
A managerial control that sets the minimum configuration standard for routers, such as banning local accounts, disabling unnecessary services and requiring a firewall.
S
- Scarcity
A social engineering tactic that creates a sense of limited availability: limited supply, not limited time.
- Screened subnet
A network segment, created with firewall zones and rules, between the internet and the internal network that holds public-facing resources; a lower security zone.
- Script kiddie
A low-skilled adversary who uses tools developed by others without understanding how they work, often for money or recognition.
- Security awareness training
Training that teaches employees to detect social engineering, avoid badging others in and prevent device theft.
- Security control
A safeguard that protects confidentiality, integrity or availability, classified by type (physical, technical, managerial) and function (preventative, detective, corrective).
- Security information and event management (SIEM)
A system that collects and analyzes data from many sources to detect attack patterns and alert analysts, who resolve or escalate the alert.
- Service set identifier (SSID)
The name of a wireless network, announced in beacon frames.
- Shared secret
A word or phrase known only to two people, used to verify each other's identity in high-stakes situations.
- Shoulder surfing
A physical attack where the adversary watches, or records with a camera, someone accessing sensitive information to use it later.
- Signature-based detection
Detection that compares data to a database of known indicators of compromise; fast, almost no false positives, but cannot detect new attacks.
- Smurf attack
A denial-of-service attack: internet control message protocol (ICMP) requests sent to a broadcast address with the victim's address forged as the source, so all replies flood the victim.
- Social engineering
An attack that uses psychological tactics to manipulate people into revealing sensitive information, downloading a malicious file or clicking a malicious link.
- Split tunneling
A virtual private network (VPN) setup where some traffic goes through the VPN and some goes directly to the internet at the same time; VPN policies often prohibit it.
- Stateful firewall
A firewall that tracks the state of connections passing through it and filters by connection-related rules as well as header information.
- Stateless firewall
A firewall that filters each packet using header information such as internet protocol (IP) addresses, ports and protocols.
- Subnetting
Creating separate subnets based on internet protocol (IP) addressing so a compromised device exposes fewer others.
- Switch
A device that joins hosts within a local area network (LAN) and forwards each frame only to the port where the destination media access control (MAC) address was seen.
T
- Tailgating
A physical attack where the adversary follows close behind an authorized person into a restricted area without that person noticing.
- Technical control
A security control type for the digital space, such as firewalls, anti-malware software and encryption.
- Threat
Anything that could exploit a vulnerability to cause harm, including human adversaries and natural disasters.
- Transference
A risk strategy: move the burden of the risk to another entity, such as an insurer, a government or consumers.
- Transnational criminal organization
An adversary group that seeks money, mainly through ransomware and stealing intellectual property to sell.
- Triangulation
Locating a signal's source by measuring its strength from several positions.
U
- Uninterruptible power supply (UPS)
A battery backup that keeps a device running during a power outage; generators provide power at larger scale.
- Urgency
A social engineering tactic where the adversary creates a reason or deadline for the target to act quickly.
V
- Virtual local area network (VLAN)
A logical network created on switches that separates devices physically connected to the same central switches.
- Virtual private network (VPN)
A service that encrypts all your traffic to the VPN operator's system, hiding it from the local network and service provider but not from the VPN provider.
- Vulnerability
A weakness or flaw that could allow an asset to be compromised.
- Vulnerability scanner
An automated tool that checks networks, devices and applications for known vulnerabilities and reports what it finds.
W
- War driving
Detecting a target's wireless network beacons while driving or walking around it, to learn the network type and where the signal leaks outside.
- Wireless access point (WAP)
A device that connects wireless devices to a wired local area network (LAN) by radio and announces the network in beacon frames.
- Workstation security policy
A policy that sets the measures for protecting a physical workplace, such as locking devices, clearing sensitive papers, privacy screens and power protection.
- WPA3
Wi-Fi Protected Access 3, currently the strongest wireless encryption protocol; Wired Equivalent Privacy (WEP), Wi-Fi Protected Setup (WPS) and the original Wi-Fi Protected Access (WPA) have known vulnerabilities.
Z
- Zero day
An undocumented vulnerability that defenders do not know about yet, discovered and used by high-skilled adversaries.
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