Terms
Alphabetical index of published term entries. Use the letter rail to jump.
- accreditorUpdated Jan 06, 2026
A management official who has been designated to have the formal authority to "accredit" an information system, i.e., to authorize the operation of, and the processing of sensitive data in, the system and to accept the residual risk associated with the system. (See: accreditation, residual risk.)
- accuracyUpdated Jan 05, 2026
Closeness of computations or estimates to the exact or true values that the statistics were intended to measure.
- accuracy (absolute)Updated Jan 05, 2026
The degree of conformity of a measured or calculated value to the true value, typically based on a global reference system. For time, the global reference can be based on the following time scales: UTC, International Atomic Time (TAI), or GPS. For position, the global reference can be WGS 84.
- accuracy (relative)Updated Jan 05, 2026
The degree of agreement between measured or calculated values among the devices and applications dependent on the position, navigation, or time data at an instant in time.
- Acquire InfrastructureUpdated Jan 03, 2026
Adversaries may buy, lease, rent, or obtain infrastructure that can be used during targeting. A wide variety of infrastructure exists for hosting and orchestrating adversary operations. Infrastructure solutions include physical or cloud servers, domains, and third party web services.(Citation: TrendmicroHideoutsLease) Some infrastructure providers offer free trial periods, enabling infrastructure acquisition at limited to no cost.(Citation: Free Trial PurpleUrchin) Additionally, botnets are available for rent or purchase.
- acquirerUpdated Jan 06, 2026
Stakeholder that acquires or procures a product or service.
- acquisitionUpdated Jan 05, 2026
Process of obtaining a system, product, or service.
- Activate Firmware Update ModeUpdated Jan 06, 2026
Adversaries may activate firmware update mode on devices to prevent expected response functions from engaging in reaction to an emergency or process malfunction. For example, devices such as protection relays may have an operation mode designed for firmware installation. This mode may halt process monitoring and related functions to allow new firmware to be loaded. A device left in update mode may be placed in an inactive holding state if no firmware is provided to it. By entering and leaving a device in this mode, the adversary may deny its usual functionalities.
- activationUpdated Jan 05, 2026
The process of inputting an activation factor into a multi factor authenticator to enable its use for authentication.
- activation dataUpdated Jan 06, 2026
A pass phrase, personal identification number (PIN), biometric data, or other mechanisms of equivalent authentication robustness used to protect access to any use of a private key, except for private keys associated with System or Device certificates.
- activation factorUpdated Jan 05, 2026
An additional authentication factor that is used to enable successful authentication with a multi factor authenticator.
- Activation/IssuanceUpdated Jan 05, 2026
A process that includes the procurement of FIPS approved blank PIV Cards or hardware/software tokens (for Derived PIV Credential), initializing them using appropriate software and data elements, personalization of these cards/tokens with the identity credentials of authorized subjects, and pick up/delivery of the personalized cards/tokens to the authorized subjects, along with appropriate instructions for protection and use.
- activation secretUpdated Jan 05, 2026
A password that is used locally as an activation factor for a multi factor authenticator.
- active attackUpdated Jan 06, 2026
An attack on a secure communication protocol where the attacker transmits data to the claimant, Credential Service Provider (CSP), verifier, or Relying Party (RP). Examples of active attacks include man in the middle (MitM), impersonation, and session hijacking.
- active contentUpdated Jan 06, 2026
Electronic documents that can carry out or trigger actions automatically on a computer platform without the intervention of a user.
- active cyber defenseUpdated Jan 05, 2026
Synchronized, real time capability to discover, detect, analyze, and mitigate threats and vulnerabilities.
- Active DirectoryUpdated Jan 05, 2026
A Microsoft directory service for the management of identities in Windows domain networks.
- Active Security TestingUpdated Jan 05, 2026
Security testing that involves direct interaction with a target, such as sending packets to a target.
- Active stateUpdated Jan 05, 2026
A lifecycle state for a key in which the key may be used to cryptographically protect information (e.g., encrypt plaintext or generate a digital signature), to cryptographically process previously protected information (e.g., decrypt ciphertext or verify a digital signature) or both.
- Active TagUpdated Jan 05, 2026
A tag that relies on a battery for power.
- active userUpdated Jan 06, 2026
See: secondary definition under "system user".
- active wiretappingUpdated Jan 06, 2026
A wiretapping attack that attempts to alter data being communicated or otherwise affect data flow. (See: wiretapping. Compare: active attack, passive wiretapping.)
- ActivitiesUpdated Jan 05, 2026
An assessment object that includes specific protection related pursuits or actions supporting an information system that involve people (e.g., conducting system backup operations, monitoring network traffic).
- activityUpdated Jan 05, 2026
Set of cohesive tasks of a process.
- ActorUpdated Jan 05, 2026
See threat actor.
- Actual Residual RiskUpdated Jan 05, 2026
The risk remaining after management has taken action to alter its severity.
- Actual StateUpdated Jan 05, 2026
The observable state or behavior of an assessment object (device, software, person, credential, account, etc.) at the point in time when the collector generates security related information. In particular, the actual state includes the states or behaviors that might indicate the presence of security defects.
- Actuating CapabilityUpdated Jan 05, 2026
The ability to change something in the physical world.
- actuatorUpdated Jan 05, 2026
A device for moving or controlling a mechanism or system. It is operated by a source of energy, typically electric current, hydraulic fluid pressure, or pneumatic pressure, and converts that energy into motion. An actuator is the mechanism by which a control system acts upon an environment. The control system can be simple (a fixed mechanical or electronic system), software based (e.g., a printer driver, robot control system), or a human or other agent.
- adaptabilityUpdated Jan 05, 2026
The property of an architecture, design, and implementation that can accommodate changes to the threat model, mission or business functions, systems, and technologies without major programmatic impacts.
- Additional Authenticated DataUpdated Jan 05, 2026
The input data to the authenticated encryption function that is authenticated but not encrypted.
- Additional inputUpdated Jan 05, 2026
Information known by two parties that is cryptographically bound to the secret keying material being protected using the encryption operation.
- add-on securityUpdated Jan 06, 2026
Incorporation of new or additional hardware, software, or firmware safeguards in an operational information system.
- AddressUpdated Jan 05, 2026
The associated data string.
- addressableUpdated Jan 05, 2026
To meet the addressable implementation specifications, a covered entity or business associate must (i) assess whether each implementation specification is a reasonable and appropriate safeguard in its environment, when analyzed with reference to the likely contribution to protecting the electronic protected health information; and (ii) as applicable to the covered entity or business associate (A) Implement the implementation specification if reasonable and appropriate; or (B) if implementing the implementation specification is not reasonable and appropriate—(1) document why it would not be reasonable and appropriate to implement the implementation specification; and (2) implement an equivalent alternative measure if reasonable and appropriate.
- Address Resolution Protocol (ARP)Updated Jan 05, 2026
A protocol used to obtain a node’s physical address. A client station broadcasts an ARP request onto the network with the Internet Protocol (IP) address of the target node with which it wishes to communicate, and with that address the node responds by sending back its physical address so that packets can be transmitted to it.
- adequate securityUpdated Jan 06, 2026
Security commensurate with the risk and the magnitude of harm resulting from the loss, misuse, or unauthorized access to or modification of information.
- Ad Hoc HIEsUpdated Jan 05, 2026
An Ad Hoc HIE occurs when two healthcare organizations exchange health information, usually under the precondition of familiarity and trust, using existing and usual office infrastructure such as mail, fax, e mail and phone calls.
- Ad Hoc NetworkUpdated Jan 05, 2026
A wireless network that allows easy connection establishment between wireless client devices in the same physical area without the use of an infrastructure device, such as an access point or a base station.
- adj-RIB-InUpdated Jan 05, 2026
Routes learned from inbound update messages from BGP peers.
- adj-RIB-OutUpdated Jan 05, 2026
Routes that the BGP router will advertise, based on its local policy, to its peers.
- Adjudicative EntityUpdated Jan 05, 2026
An agency authorized by law, Executive Order, designation by the Security Executive Agent, or delegation by the Suitability & Credentialing Executive Agent to make an adjudication. Adjudication has the meaning provided in [Executive Order 13764], “(a) ‘Adjudication’ means the evaluation of pertinent data in a background investigation, as well as any other available information that is relevant and reliable, to determine whether a covered individual is: (i) suitable for Government employment; (ii) eligible for logical and physical access; (iii) eligible for access to classified information; (iv) eligible to hold a sensitive position; or (v) fit to perform work for or on behalf of the Government as a Federal employee, contractor, or non appropriated fund employee.”
- Administrative domainUpdated Jan 05, 2026
A logical collection of hosts and network resources (e.g., department, building, company, organization) governed by common policies.
- administrative incident (COMSEC)Updated Jan 05, 2026
A violation of procedures or practices dangerous to security that is not serious enough to jeopardize the integrity of a controlled cryptographic item (CCI), but requires corrective action to ensure the violation does not recur or possibly lead to a reportable COMSEC incident.
- administrative securityUpdated Jan 06, 2026
Management procedures and constraints to prevent unauthorized access to a system. (See: "third law" under "Courtney's laws", manager, operational security, procedural security, security architecture. Compare: technical security.)
- administratorUpdated Jan 06, 2026
A person that is responsible for configuring, maintaining, and administering the TOE in a correct manner for maximum security. (See: administrative security.)
- Advanced Encryption StandardUpdated Jan 06, 2026
A U.S. Government standard [FP197] (the successor to DES) that (a) specifies "the AES algorithm", which is a symmetric block cipher that is based on Rijndael and uses key sizes of 128, 192, or 256 bits to operate on a 128 bit block, and (b) states policy for using that algorithm to protect unclassified, sensitive data.
- advanced persistent threatUpdated Jan 06, 2026
An adversary that possesses sophisticated levels of expertise and significant resources which allow it to create opportunities to achieve its objectives by using multiple attack vectors (e.g., cyber, physical, and deception).
- adversaryUpdated Jan 06, 2026
An individual, group, organization, or government that conducts or has the intent to conduct detrimental activities.
- Adversary-in-the-MiddleUpdated Jan 06, 2026
Adversaries may attempt to position themselves between two or more networked devices using an adversary in the middle (AiTM) technique to support follow on behaviors such as Network Sniffing, Transmitted Data Manipulation, or replay attacks (Exploitation for Credential Access). By abusing features of common networking protocols that can determine the flow of network traffic (e.g. ARP, DNS, LLMNR, etc.), adversaries may force a device to communicate through an adversary controlled system so they can collect information or perform additional actions.(Citation: Rapid7 MiTM Basics)