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MediumSplunk security contentMauricio Velazco +1

O365 Mailbox Folder Read Permission Granted

The following analytic identifies instances where read permissions are granted to mailbox folders within an Office 365 environment. It detects this activity by monitoring the `o365_management_activity` data source…

Description

The following analytic identifies instances where read permissions are granted to mailbox folders within an Office 365 environment. It detects this activity by monitoring the `o365_management_activity` data source for the `Set-MailboxFolderPermission` and `Add-MailboxFolderPermission` operations. This behavior is significant as it may indicate unauthorized access or changes to mailbox folder permissions, potentially exposing sensitive email content. If confirmed malicious, an attacker could gain unauthorized access to read email communications, leading to data breaches or information leakage.

Detection logic

Detection requirements

Platform
Office SuiteWindows

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

Log source category
o365_modifyfolderpermissions

Known benign triggers

  • Mailbox folder permissions may be configured for legitimate purposes, filter as needed.

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