NIST SP 800-53 Rev. 5 · Audit and Accountability
AU-9 on Microsoft Sentinel
Audit logging disabled or deleted — a published KQL query you can run against Microsoft Sentinel / Log Analytics, with the evidence it needs, the settings you decide, and what a result does and does not establish.
Why this matters
Someone switched off the recording of what happens on the system
Systems keep a record of significant events, and that record is how anyone reconstructs what happened after an incident. It is also the first thing an intruder turns off, because everything they do afterwards goes unrecorded. Switching it off is a legitimate administrative action, so it does not look like an attack — which is why it works.
Why this check earns its place. The check does not decide whether the person was allowed to do it. It surfaces that it happened, so a human can ask, which is the only correct handling for an action that is sometimes routine and sometimes the first move of a break-in.
- What it reads
- The organization's own record of administrative actions taken on its systems.
- What it reports
- Occasions when the recording of system events was stopped, deleted, or altered.
See related public disclosures on the Signals page →
What this finds
Audit logging configuration stopped, deleted, or modified; the reviewer determines whether the actor was authorized.
The requirement
The organization must protect audit information and audit logging tools from unauthorized access, modification, and deletion.
NIST SP 800-53 Rev. 5 — AU-9 (Protection of Audit Information).
NIST requires protection of audit information. Which logging surfaces are in scope, which identities may legitimately modify logging configuration, and the expected response time are organization-defined.
How this maps to the CISA performance goals
The Cross-Sector Cybersecurity Performance Goals are a voluntary baseline published by CISA — the U.S. federal agency for critical-infrastructure cybersecurity — written for organizations too small to employ security staff. This control speaks to:
- 3.Q — Maintain log collection & storage
The goal requires logs to be collected and retained; the pack finds logging switched off or records removed.
See the full coverage map, including the goals no query can answer →
Evidence this query needs
None. This query runs on platform telemetry alone — there is no file to prepare and nothing to export.
The query
Published as au-9-audit-tampering.azure.kql. Reads AzureActivity. Requires: Log Analytics Reader.
Before this returns anything,
AzureActivity has to be reaching Microsoft Sentinel / Log Analytics. If not, the query reports nothing found — which looks
exactly like nothing wrong. What has to be switched on first →
// AU-9 -- diagnostic settings or log destinations removed or modified
let Lookback = 7d;
let SensitiveOps = dynamic([
"MICROSOFT.INSIGHTS/DIAGNOSTICSETTINGS/DELETE",
"MICROSOFT.INSIGHTS/DIAGNOSTICSETTINGS/WRITE",
"MICROSOFT.OPERATIONALINSIGHTS/WORKSPACES/DELETE",
"MICROSOFT.SECURITYINSIGHTS/ALERTRULES/DELETE"]);
AzureActivity
| where TimeGenerated > ago(Lookback)
| where ActivityStatusValue =~ "Success"
| where toupper(OperationNameValue) in (SensitiveOps)
| project TimeGenerated, Caller, CallerIpAddress,
OperationNameValue, ResourceId = tolower(ResourceId),
CorrelationId, SourceSystem = "Azure Resource Manager"
| order by TimeGenerated descOpen this pack on Microsoft Sentinel to adjust the settings and download it →
The interactive version opens on Microsoft Sentinel — the platform on this page — even if your environment profile does not list it.
Settings you decide
NIST states the objective and leaves these to your organization. The interactive version of this pack applies them to the query for you.
- Review window (days) (default 7)
- How far back to examine logging-configuration changes.
Running it continuously
Sentinel near-real-time (NRT) rule
Rule type: NRT (near-real-time) query rule
Run frequency: Continuous (approx. 1 minute)
Trigger: Any result
Entity mapping: Account -> Caller | IP -> CallerIpAddress
Severity: High
MITRE tactic: Defense Evasion (T1562.008)
Incident: Create incident immediately
Suppression: None -- every event reviewed
Tuning note: Allowlist platform automation identities firstThe only rule in this set deployed as near-real-time rather than scheduled. Log tampering is time-critical: an hourly schedule gives an adversary an hour of unlogged activity.
What a result does not prove
A logging configuration change is not automatically malicious. It is, however, one of the few conditions where the cost of a slow review is high enough to justify treating it as urgent by default.
Validation status for this platform: Not tenant-validated. Structure, query generation, and preflight are covered by the project's automated test suites. This pack has not been executed against a live tenant, account, or index. Validate it in a non-production scope before relying on any result.
Before you act on a result
- Was this part of an approved change or platform migration?
- Is the actor an automation identity that should be allowlisted?
- Was logging restored, and was there a gap in coverage?
- Does other activity by the same actor in the surrounding window warrant investigation?
Common questions
- How do I check for audit logging disabled or deleted in Microsoft Sentinel?
- Run the published KQL query on this page against Microsoft Sentinel / Log Analytics. It reads AzureActivity and reports: Audit logging configuration stopped, deleted, or modified; the reviewer determines whether the actor was authorized.
- What permissions are needed to run this Microsoft Sentinel query?
- Log Analytics Reader.
- Does a result from this query mean the control has failed?
- A logging configuration change is not automatically malicious. It is, however, one of the few conditions where the cost of a slow review is high enough to justify treating it as urgent by default.
Terms used on this page
- NIST SP 800-53the U.S. federal catalogue of security requirements
- The catalogue of security and privacy requirements published by the National Institute of Standards and Technology, a U.S. federal agency. U.S. government systems are measured against it, and many private organizations adopt it voluntarily. Each requirement has an identifier such as AC-2. Official source →
- CISACybersecurity and Infrastructure Security Agency
- The U.S. federal agency responsible for national critical-infrastructure cybersecurity. Its publications are works of the U.S. government and are free to use. Official source →
- KQLKusto Query Language
- The language used to ask questions of data held in Microsoft Sentinel. A query written in it is text, like a spreadsheet formula, and can be read before it is run.
- CPGCross-Sector Cybersecurity Performance Goals
- A voluntary baseline of security practices published by the U.S. Cybersecurity and Infrastructure Security Agency, written specifically for organizations too small to employ security staff. It is a short, plainly written starting list rather than a full standard. Official source →
- not tenant-validatednever executed against real data
- The check has passed the project's automated tests for structure and syntax, but has never been run against real data anywhere. Test it in a safe scope before relying on any result.
The same control on other platforms
- AU-9 on AWS — SQL (Athena) + Lambda
- AU-9 on Splunk — SPL
- All platforms for AU-9