M365 Exchange Mailbox Audit Logging Bypass Added
Detects the occurrence of mailbox audit bypass associations. The mailbox audit is responsible for logging specified mailbox events (like accessing a folder or a message or permanently deleting a message). However,…
Description
Detects the occurrence of mailbox audit bypass associations. The mailbox audit is responsible for logging specified mailbox events (like accessing a folder or a message or permanently deleting a message). However, actions taken by some authorized accounts, such as accounts used by third-party tools or accounts used for lawful monitoring, can create a large number of mailbox audit log entries and may not be of interest to your organization. Because of this, administrators can create bypass associations, allowing certain accounts to perform their tasks without being logged. Attackers can abuse this allowlist mechanism to conceal actions taken, as the mailbox audit will log no activity done by the account.
Detection logic
Its licence does not clear it for publishing here
Sunturai publishes a detection's own text where the licence it arrived under has been reviewed and permits it, and Elastic License 2.0 has not. The query as its source wrote it, its canonical form and the hash that pins this revision are in the workspace record.
Detection requirements
- Platform
- ContainersESXiIaaSIdentity ProviderLinuxmacOSNetwork DevicesOffice SuiteSaaSWindows
The rule states no platform. This is derived from the 2 ATT&CK techniques it maps to.
- Log source category
- event_index
Known benign triggers
- Legitimate allowlisting of noisy accounts
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| twitter.com/misconfig/status/1476144066807140355 | Only this detection cites it |
From the source
- At source
- Open at source
- Upstream identifier
- 675239ea-c1bc-4467-a6d3-b9e2cc7f676d
- Tagged by the source as
- Data Source: Microsoft 365Data Source: Microsoft 365 Audit LogsDomain: CloudDomain: EmailDomain: SaaSNoise: MediumPerformance: FastPlatform: Microsoft 365Resources: Investigation GuideRule Type: Custom Query (KQL)Service: Microsoft Exchange OnlineTactic: Defense EvasionTactic: Initial Access
Licence
- Published under
- Elastic License 2.0Read the licence
- Attribution
- Required
Authorship
- Written by
- Published
- Sep 20, 2026
- Version
- 3