Potential Persistence Via Outlook Today Page Registry Modification

SigmaHQ Detections@sigmaHQ

•updated Oct 23, 2025•0•12

This rule detects potential persistence activity by monitoring modifications to the Outlook Today page settings in the Windows Registry. Attackers can leverage this feature by setting a custom URL in the registry keys `Software\Microsoft\Office\<version>\Outlook\Today\URL` or `Software\Microsoft\Office\<version>\Outlook\Today\UserDefinedUrl`, along with setting the `Stamp` value to `0x00000001`. This allows for the execution of arbitrary code when Outlook is opened, providing a persistent foothold on the system.