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InformationalSplunk security contentSteven Dick

O365 Email Send and Hard Delete Suspicious Behavior

The following analytic identifies when an O365 email account sends and then hard deletes email with within a short period (within 1 hour). This behavior may indicate a compromised account where the threat actor is…

Description

The following analytic identifies when an O365 email account sends and then hard deletes email with within a short period (within 1 hour). This behavior may indicate a compromised account where the threat actor is attempting to remove forensic artifacts or evidence of activity. Threat actors often use this technique to prevent defenders and victims from knowing the account has been compromised. --- Some account owner legitimate behaviors can trigger this alert, however these actions may not be aligned with organizational expectations / best practice behaviors.

Detection logic

Detection requirements

Platform
ContainersESXiIaaSLinuxmacOSOffice SuiteWindows

The rule states no platform. This is derived from the 3 ATT&CK techniques it maps to.

Log source category
office_365_universal_audit_log

Known benign triggers

  • Users that habitually/proactively cleaning the recoverable items folder may trigger this alert.

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