Control: The information system:
B. Takes the following additional actions: `{`Assignment: organisation-defined actions to be taken (e.g., shut down information system, overwrite oldest audit records, stop generating audit records)`}`.
Supplemental Guidance: Audit processing failures include, for example, software / hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded. Organisations may choose to define additional actions for different audit processing failures (e.g., by type, by location, by severity, or a combination of such factors). This control applies to each audit data storage repository (i.e., distinct information system component where audit records are stored), the total audit storage capacity of organisations (i.e., all audit data storage repositories combined), or both.
Response to Audit Processing Failures Control Enhancements:
AU-5 (1) Response to Audit Processing Failures - Audit storage capacity
The information system provides a warning to [Assignment: organisation-defined personnel, roles, and/or locations] within [Assignment: organisation-defined time period] when allocated audit record storage volume reaches [Assignment: organisation-defined percentage] of repository maximum audit record storage capacity.
Supplemental Guidance: Organisations may have multiple audit data storage repositories distributed across multiple information system components, with each repository having different storage volume capacities.
AU-5 (2) Response to Audit Processing Failures - Real time alerts
The information system provides an alert in [Assignment: organisation-defined real-time period] to [Assignment: organisation-defined personnel, roles, and/or locations] when the following audit failure events occur: [Assignment: organisation-defined audit failure events requiring real-time alerts].
Supplemental Guidance: Alerts provide organisations 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).
AU-5 (3) Response to Audit Processing Failures - Configurable traffic volume thresholds
The information system enforces configurable network communications traffic volume thresholds reflecting limits on auditing capacity and [Selection: rejects; delays] network traffic above those thresholds.
Supplemental Guidance: Organisations have the capability to reject or delay the processing of network communications traffic if auditing such traffic is determined to exceed the storage capacity of the information system audit function. The rejection or delay response is triggered by the established organisational traffic volume thresholds which can be adjusted based on changes to audit storage capacity.
AU-5 (4) Response to Audit Processing Failures - Shutdown on failure
The information system invokes a [Selection: full system shutdown; partial system shutdown; degraded operational mode with limited mission/business functionality available] in the event of [Assignment: organisation-defined audit failures], unless an alternate audit capability exists.
Supplemental Guidance: Organisations determine the types of audit failures that can trigger automatic information system shutdowns or degraded operations. Because of the importance of ensuring mission/business continuity, organisations may determine that the nature of the audit failure is not so severe that it warrants a complete shutdown of the information system supporting the core organisational missions/business operations. In those instances, partial information system shutdowns or operating in a degraded mode with reduced capability may be viable alternatives.
Related control: AU-15.