NIST SP 800-53 Learning Center
Study this control family as a connected set of risk outcomes, implementation decisions, evidence expectations, and assessment questions.
Control family
Use the family as a planning boundary, but assess each selected control against the system context, inherited services, organization-defined parameters, and evidence available from real operations.
Family catalog
Base controls open full profiles. Enhancement results link directly to the corresponding enhancement section on the parent control page.
Audit and accountability policy and procedures address the controls in the AU family that are implemented within systems and organizations. The risk management strategy is an important factor in establishing such policies and procedures. Policies and procedures contribute to security and privacy assurance. Therefore, it is important that security and privacy
An event is an observable occurrence in a system. The types of events that require logging are those events that are significant and relevant to the security of systems and the privacy of individuals. Event logging also supports specific monitoring and auditing needs. Event types include password changes, failed logons or failed accesses related to systems,
Audit record content that may be necessary to support the auditing function includes event descriptions (item a), time stamps (item b), source and destination addresses (item c), user or process identifiers (items d and f), success or fail indications (item e), and filenames involved (items a, c, e, and f) . Event outcomes include indicators of event success
Organizations consider the types of audit logging to be performed and the audit log processing requirements when allocating audit log storage capacity. Allocating sufficient audit log storage capacity reduces the likelihood of such capacity being exceeded and resulting in the potential loss or reduction of audit logging capability.
Audit logging process failures include software and hardware errors, failures in audit log capturing mechanisms, and reaching or exceeding audit log storage capacity. Organization-defined actions include overwriting oldest audit records, shutting down the system, and stopping the generation of audit records. Organizations may choose to define additional acti
Audit record review, analysis, and reporting covers information security- and privacy-related logging performed by organizations, including logging that results from the monitoring of account usage, remote access, wireless connectivity, mobile device connection, configuration settings, system component inventory, use of maintenance tools and non-local mainte
Audit record reduction is a process that manipulates collected audit log information and organizes it into a summary format that is more meaningful to analysts. Audit record reduction and report generation capabilities do not always emanate from the same system or from the same organizational entities that conduct audit logging activities. The audit record r
Time stamps generated by the system include date and time. Time is commonly expressed in Coordinated Universal Time (UTC), a modern continuation of Greenwich Mean Time (GMT), or local time with an offset from UTC. Granularity of time measurements refers to the degree of synchronization between system clocks and reference clocks (e.g., clocks synchronizing wi
Audit information includes all information needed to successfully audit system activity, such as audit records, audit log settings, audit reports, and personally identifiable information. Audit logging tools are those programs and devices used to conduct system audit and logging activities. Protection of audit information focuses on technical protection and
Types of individual actions covered by non-repudiation include creating information, sending and receiving messages, and approving information. Non-repudiation protects against claims by authors of not having authored certain documents, senders of not having transmitted messages, receivers of not having received messages, and signatories of not having signed
Organizations retain audit records until it is determined that the records are no longer needed for administrative, legal, audit, or other operational purposes. This includes the retention and availability of audit records relative to Freedom of Information Act (FOIA) requests, subpoenas, and law enforcement actions. Organizations develop standard categories
Audit records can be generated from many different system components. The event types specified in [AU-2d](#au-2_smt.d) are the event types for which audit logs are to be generated and are a subset of all event types for which the system can generate audit records.
Unauthorized disclosure of information is a form of data leakage. Open-source information includes social networking sites and code-sharing platforms and repositories. Examples of organizational information include personally identifiable information retained by the organization or proprietary information generated by the organization.
Session audits can include monitoring keystrokes, tracking websites visited, and recording information and/or file transfers. Session audit capability is implemented in addition to event logging and may involve implementation of specialized session capture technology. Organizations consider how session auditing can reveal information about individuals that m
NIST SP 800-53 AU-15 Alternate Audit Logging Capability.
When organizations use systems or services of external organizations, the audit logging capability necessitates a coordinated, cross-organization approach. For example, maintaining the identity of individuals who request specific services across organizational boundaries may often be difficult, and doing so may prove to have significant performance and priva
NIST SP 800-53 enhancement AU-2(1) Compilation of Audit Records from Multiple Sources.
NIST SP 800-53 enhancement AU-2(2) Selection of Audit Events by Component.
NIST SP 800-53 enhancement AU-2(3) Reviews and Updates.
NIST SP 800-53 enhancement AU-2(4) Privileged Functions.
The ability to add information generated in audit records is dependent on system functionality to configure the audit record content. Organizations may consider additional information in audit records including, but not limited to, access control or flow control rules invoked and individual identities of group account users. Organizations may also consider l
NIST SP 800-53 enhancement AU-3(2) Centralized Management of Planned Audit Record Content.
Limiting personally identifiable information in audit records when such information is not needed for operational purposes helps reduce the level of privacy risk created by a system.
Audit log transfer, also known as off-loading, is a common process in systems with limited audit log storage capacity and thus supports availability of the audit logs. The initial audit log storage is only used in a transitory fashion until the system can communicate with the secondary or alternate system allocated to audit log storage, at which point the au
Organizations may have multiple audit log storage repositories distributed across multiple system components with each repository having different storage volume capacities.
Alerts provide organizations with urgent messages. Real-time alerts provide these messages at information technology speed (i.e., the time from event detection to alert occurs in seconds or less).
Organizations have the capability to reject or delay the processing of network communications traffic if audit logging information about such traffic is determined to exceed the storage capacity of the system audit logging function. The rejection or delay response is triggered by the established organizational traffic volume thresholds that can be adjusted b
Organizations determine the types of audit logging failures that can trigger automatic system shutdowns or degraded operations. Because of the importance of ensuring mission and business continuity, organizations may determine that the nature of the audit logging failure is not so severe that it warrants a complete shutdown of the system supporting the core
Since an alternate audit logging capability may be a short-term protection solution employed until the failure in the primary audit logging capability is corrected, organizations may determine that the alternate audit logging capability need only provide a subset of the primary audit logging functionality that is impacted by the failure.
Organizational processes that benefit from integrated audit record review, analysis, and reporting include incident response, continuous monitoring, contingency planning, investigation and response to suspicious activities, and Inspector General audits.
NIST SP 800-53 enhancement AU-6(2) Automated Security Alerts.
Organization-wide situational awareness includes awareness across all three levels of risk management (i.e., organizational level, mission/business process level, and information system level) and supports cross-organization awareness.
Automated mechanisms for centralized reviews and analyses include Security Information and Event Management products.
Integrated analysis of audit records does not require vulnerability scanning, the generation of performance data, or system monitoring. Rather, integrated analysis requires that the analysis of information generated by scanning, monitoring, or other data collection activities is integrated with the analysis of audit record information. Security Information a
The correlation of physical audit record information and the audit records from systems may assist organizations in identifying suspicious behavior or supporting evidence of such behavior. For example, the correlation of an individual’s identity for logical access to certain systems with the additional physical security information that the individual was pr
Organizations specify permitted actions for system processes, roles, and users associated with the review, analysis, and reporting of audit records through system account management activities. Specifying permitted actions on audit record information is a way to enforce the principle of least privilege. Permitted actions are enforced by the system and includ
Full text analysis of privileged commands requires a distinct environment for the analysis of audit record information related to privileged users without compromising such information on the system where the users have elevated privileges, including the capability to execute privileged commands. Full text analysis refers to analysis that considers the full
Nontechnical sources include records that document organizational policy violations related to harassment incidents and the improper use of information assets. Such information can lead to a directed analytical effort to detect potential malicious insider activity. Organizations limit access to information that is available from nontechnical sources due to i
Events of interest can be identified by the content of audit records, including system resources involved, information objects accessed, identities of individuals, event types, event locations, event dates and times, Internet Protocol addresses involved, or event success or failure. Organizations may define event criteria to any degree of granularity require
NIST SP 800-53 enhancement AU-7(2) Automatic Sort and Search.
NIST SP 800-53 enhancement AU-8(1) Synchronization with Authoritative Time Source.
NIST SP 800-53 enhancement AU-8(2) Secondary Authoritative Time Source.
Writing audit trails to hardware-enforced, write-once media applies to the initial generation of audit trails (i.e., the collection of audit records that represents the information to be used for detection, analysis, and reporting purposes) and to the backup of those audit trails. Writing audit trails to hardware-enforced, write-once media does not apply to
Storing audit records in a repository separate from the audited system or system component helps to ensure that a compromise of the system being audited does not also result in a compromise of the audit records. Storing audit records on separate physical systems or components also preserves the confidentiality and integrity of audit records and facilitates t
Cryptographic mechanisms used for protecting the integrity of audit information include signed hash functions using asymmetric cryptography. This enables the distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash.
Individuals or roles with privileged access to a system and who are also the subject of an audit by that system may affect the reliability of the audit information by inhibiting audit activities or modifying audit records. Requiring privileged access to be further defined between audit-related privileges and other privileges limits the number of users or rol
Organizations may choose different selection options for different types of audit information. Dual authorization mechanisms (also known as two-person control) require the approval of two authorized individuals to execute audit functions. To reduce the risk of collusion, organizations consider rotating dual authorization duties to other individuals. Organiza
Restricting privileged user or role authorizations to read-only helps to limit the potential damage to organizations that could be initiated by such users or roles, such as deleting audit records to cover up malicious activity.
Storing auditing information on a system component running a different operating system reduces the risk of a vulnerability specific to the system, resulting in a compromise of the audit records.
Binding identities to the information supports audit requirements that provide organizational personnel with the means to identify who produced specific information in the event of an information transfer. Organizations determine and approve the strength of attribute binding between the information producer and the information based on the security category
Validating the binding of the information producer identity to the information prevents the modification of information between production and review. The validation of bindings can be achieved by, for example, using cryptographic checksums. Organizations determine if validations are in response to user requests or generated automatically.
Chain of custody is a process that tracks the movement of evidence through its collection, safeguarding, and analysis life cycle by documenting each individual who handled the evidence, the date and time the evidence was collected or transferred, and the purpose for the transfer. If the reviewer is a human or if the review function is automated but separate
Validating the binding of the information reviewer identity to the information at transfer or release points prevents the unauthorized modification of information between review and the transfer or release. The validation of bindings can be achieved by using cryptographic checksums. Organizations determine if validations are in response to user requests or g
NIST SP 800-53 enhancement AU-10(5) Digital Signatures.
Organizations need to access and read audit records requiring long-term storage (on the order of years). Measures employed to help facilitate the retrieval of audit records include converting records to newer formats, retaining equipment capable of reading the records, and retaining the necessary documentation to help personnel understand how to interpret th
Audit trails are time-correlated if the time stamps in the individual audit records can be reliably related to the time stamps in other audit records to achieve a time ordering of the records within organizational tolerances.
Audit records that follow common standards promote interoperability and information exchange between devices and systems. Promoting interoperability and information exchange facilitates the production of event information that can be readily analyzed and correlated. If logging mechanisms do not conform to standardized formats, systems may convert individual
Permitting authorized individuals to make changes to system logging enables organizations to extend or limit logging as necessary to meet organizational requirements. Logging that is limited to conserve system resources may be extended (either temporarily or permanently) to address certain threat situations. In addition, logging may be limited to a specific
Query parameters are explicit criteria that an individual or automated system submits to a system to retrieve data. Auditing of query parameters for datasets that contain personally identifiable information augments the capability of an organization to track and understand the access, usage, or sharing of personally identifiable information by authorized per
Automated mechanisms include commercial services that provide notifications and alerts to organizations and automated scripts to monitor new posts on websites.
Reviewing the current list of open-source information sites being monitored on a regular basis helps to ensure that the selected sites remain relevant. The review also provides the opportunity to add new open-source information sites with the potential to provide evidence of unauthorized disclosure of organizational information. The list of sites monitored c
The unauthorized use or replication of organizational information by external entities can cause adverse impacts on organizational operations and assets, including damage to reputation. Such activity can include the replication of an organizational website by an adversary or hostile threat actor who attempts to impersonate the web-hosting organization. Disco
The automatic initiation of session audits at startup helps to ensure that the information being captured on selected individuals is complete and not subject to compromise through tampering by malicious threat actors.
NIST SP 800-53 enhancement AU-14(2) Capture and Record Content.
None.
Identity preservation is applied when there is a need to be able to trace actions that are performed across organizational boundaries to a specific individual.
Due to the distributed nature of the audit information, cross-organization sharing of audit information may be essential for effective analysis of the auditing being performed. For example, the audit records of one organization may not provide sufficient information to determine the appropriate or inappropriate use of organizational information resources by
Preserving identities in audit trails could have privacy ramifications, such as enabling the tracking and profiling of individuals, but may not be operationally necessary. These risks could be further amplified when transmitting information across organizational boundaries. Implementing privacy-enhancing cryptographic techniques can disassociate individuals
NIST SP 800-53 enhancement AU-6(10) Audit Level Adjustment.
Try a shorter term or clear one of the filters.
Planned Academy connection
These titles come from the approved NIST SP 800-53 course plan. They are shown as planned coverage and do not claim a public lesson URL before publication.
