Control statement
- a.Protect audit information and audit logging tools from unauthorized access, modification, and deletion; and
- b.Alert [Organization-defined: personnel or roles] upon detection of unauthorized access, modification, or deletion of audit information.
Discussion
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 limits the ability to access and execute audit logging tools to authorized individuals. Physical protection of audit information is addressed by both media protection controls and physical and environmental protection controls.
Organization-defined parameters
These values must be resolved through the organization’s tailoring and governance process. Bracketed parameter references in the control text identify where a decision is required.
From control text to operational evidence
Use Protection of Audit Information as a testable risk decision. Translate the official statement into accountable people, repeatable processes, configured technology, and evidence that demonstrates the outcome over time. In this family, pay particular attention to audit event design, trustworthy collection, retention, review, and investigation support.
Implementation workflow
- Define the control boundary, responsible owner, inherited portions, and systems or processes in scope.
- Resolve each organization-defined parameter before declaring the control implemented.
- Document how the implementation satisfies every clause of the official control statement.
- Collect evidence as a normal byproduct of operation rather than only before an assessment.
- Review exceptions, changes, and monitoring results on a risk-based cadence.
Evidence examples
- logging standards and event-selection decisions
- sample audit records and retention settings
- time-synchronization evidence
- alert and review records
Common failure patterns
- collecting logs without defined use cases
- critical events missing from the audit trail
- retention shorter than investigative needs
- logs accessible to the same administrators being monitored
Questions practitioners should ask
- What risk decision is this control intended to support in this system?
- Which parts are implemented locally, inherited, shared, or not applicable—and what evidence supports that decision?
- Do the documented narrative, deployed configuration, operating process, and collected evidence agree?
- What event or threshold requires the implementation to be reviewed or changed?
Assessment objectives and methods
Show the assessment objective
- AU-09a.audit information and audit logging tools are protected from unauthorized access, modification, and deletion;
- AU-09b.[Organization-defined: personnel or roles] are alerted upon detection of unauthorized access, modification, or deletion of audit information.
Examine
- Audit and accountability policy
- system security plan
- privacy plan
- access control policy and procedures
- procedures addressing protection of audit information
- system design documentation
- system configuration settings and associated documentation
- system audit records
- audit tools
- other relevant documents or records
Interview
- Organizational personnel with audit and accountability responsibilities
- organizational personnel with information security and privacy responsibilities
- system/network administrators
- system developers
Test
- Mechanisms implementing audit information protection
Related controls
These relationships come from the official OSCAL catalog. They indicate useful dependencies or context, not automatic inheritance or equivalence.
Control enhancements
Enhancements add specificity, strength, or scope to the base control. Baseline badges show explicit selections in the official SP 800-53B OSCAL profiles.
AU-9(1) — Hardware Write-once Media
Write audit trails to hardware-enforced, write-once media.
Official discussion
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 the initial generation of audit records prior to being written to an audit trail. Write-once, read-many (WORM) media includes Compact Disc-Recordable (CD-R), Blu-Ray Disc Recordable (BD-R), and Digital Versatile Disc-Recordable (DVD-R). In contrast, the use of switchable write-protection media, such as tape cartridges, Universal Serial Bus (USB) drives, Compact Disc Re-Writeable (CD-RW), and Digital Versatile Disc-Read Write (DVD-RW) results in write-protected but not write-once media.
Assessment objectives and methods
audit trails are written to hardware-enforced, write-once media.
Examine
- Audit and accountability policy
- system security plan
- privacy plan
- access control policy and procedures
- procedures addressing protection of audit information
- system design documentation
- system hardware settings
- system configuration settings and associated documentation
- system storage media
- system audit records
- other relevant documents or records
Interview
- Organizational personnel with audit and accountability responsibilities
- organizational personnel with information security and privacy responsibilities
- system/network administrators
- system developers
Test
- System media storing audit trails
Related controls
AU-9(2) — Store on Separate Physical Systems or Components
Store audit records [Organization-defined: frequency] in a repository that is part of a physically different system or system component than the system or component being audited.
Official discussion
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 the management of audit records as an organization-wide activity. Storing audit records on separate systems or components applies to initial generation as well as backup or long-term storage of audit records.
Organization-defined parameters (1)
Assessment objectives and methods
audit records are stored [Organization-defined: frequency] in a repository that is part of a physically different system or system component than the system or component being audited.
Examine
- Audit and accountability policy
- system security plan
- privacy plan
- procedures addressing protection of audit information
- system design documentation
- system configuration settings and associated documentation
- system or media storing backups of system audit records
- system audit records
- other relevant documents or records
Interview
- Organizational personnel with audit and accountability responsibilities
- organizational personnel with information security and privacy responsibilities
- system/network administrators
- system developers
Test
- Mechanisms implementing the backing up of audit records
Related controls
AU-9(3) — Cryptographic Protection
Implement cryptographic mechanisms to protect the integrity of audit information and audit tools.
Official discussion
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.
Assessment objectives and methods
cryptographic mechanisms to protect the integrity of audit information and audit tools are implemented.
Examine
- Audit and accountability policy
- system security plan
- privacy plan
- access control policy and procedures
- procedures addressing protection of audit information
- system design documentation
- system hardware settings
- system configuration settings and associated documentation
- system audit records
- other relevant documents or records
Interview
- Organizational personnel with audit and accountability responsibilities
- organizational personnel with information security and privacy responsibilities
- system/network administrators
- system developers
Test
- Cryptographic mechanisms protecting the integrity of audit information and tools
Related controls
AU-9(4) — Access by Subset of Privileged Users
Authorize access to management of audit logging functionality to only [Organization-defined: subset of privileged users or roles].
Official discussion
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 roles with audit-related privileges.
Organization-defined parameters (1)
Assessment objectives and methods
access to management of audit logging functionality is authorized only to [Organization-defined: subset of privileged users or roles].
Examine
- Audit and accountability policy
- system security plan
- privacy plan
- access control policy and procedures
- procedures addressing protection of audit information
- system design documentation
- system configuration settings and associated documentation
- system-generated list of privileged users with access to management of audit functionality
- access authorizations
- access control list
- system audit records
- other relevant documents or records
Interview
- Organizational personnel with audit and accountability responsibilities
- organizational personnel with information security and privacy responsibilities
- system/network administrators
Test
- Mechanisms managing access to audit functionality
Related controls
AU-9(5) — Dual Authorization
Enforce dual authorization for [Organization-defined: au-09.05_odp.01] of [Organization-defined: audit information].
Official discussion
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. Organizations do not require dual authorization mechanisms when immediate responses are necessary to ensure public and environmental safety.
Organization-defined parameters (2)
Assessment objectives and methods
dual authorization is enforced for the [Organization-defined: au-09.05_odp.01] of [Organization-defined: audit information].
Examine
- Audit and accountability policy
- system security plan
- privacy plan
- access control policy and procedures
- procedures addressing protection of audit information
- system design documentation
- system configuration settings and associated documentation
- access authorizations
- system audit records
- other relevant documents or records
Interview
- Organizational personnel with audit and accountability responsibilities
- organizational personnel with information security and privacy responsibilities
- system/network administrators
Test
- Mechanisms implementing the enforcement of dual authorization
Related controls
AU-9(6) — Read-only Access
Authorize read-only access to audit information to [Organization-defined: subset of privileged users or roles].
Official discussion
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.
Organization-defined parameters (1)
Assessment objectives and methods
read-only access to audit information is authorized to [Organization-defined: subset of privileged users or roles].
Examine
- Audit and accountability policy
- system security plan
- privacy plan
- access control policy and procedures
- procedures addressing protection of audit information
- system design documentation
- system configuration settings and associated documentation
- system-generated list of privileged users with read-only access to audit information
- access authorizations
- access control list
- system audit records
- other relevant documents or records
Interview
- Organizational personnel with audit and accountability responsibilities
- organizational personnel with information security and privacy responsibilities
- system/network administrators
Test
- Mechanisms managing access to audit information
AU-9(7) — Store on Component with Different Operating System
Store audit information on a component running a different operating system than the system or component being audited.
Official discussion
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.
Assessment objectives and methods
audit information is stored on a component running a different operating system than the system or component being audited.
Examine
- Audit and accountability policy
- system security plan
- privacy plan
- access control policy and procedures
- procedures addressing protection of audit information
- system design documentation
- system configuration settings and associated documentation
- system audit records
- other relevant documents or records
Interview
- Organizational personnel with audit and accountability responsibilities
- organizational personnel with information security and privacy responsibilities
- system/network administrators
Test
- Mechanisms implementing operating system verification capability
- mechanisms verifying audit information storage location
Related controls
Authoritative sources
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