Malicious Mailbox Audit Bypass Association in Exchange Online (via exchange)
- Product
- m365
- Service
- exchange
- Author
- HuntRule
- Published
- 2026-09-05
- Updated
- 2026-09-05
ATT&CK techniques
Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule detects an account being added to the mailbox audit bypass list, which stops Exchange from logging that account's mailbox actions, a defense-evasion technique used to hide mailbox access and rule creation. Mailbox audit bypass is tracked in the Red Canary Threat Detection Report cloud coverage. Detecting this operation surfaces an attacker suppressing mailbox telemetry.
Reporting behind it
Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.
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