Outlook Home Page
Where this stands
2 published detections cover this technique. Every one is unverified — no rule on Siemphony has been executed against real telemetry.
What the technique is
Adversaries may abuse Microsoft Outlook's Home Page feature to obtain persistence on a compromised system. Outlook Home Page is a legacy feature used to customize the presentation of Outlook folders. This feature allows for an internal or external URL to be loaded and presented whenever a folder is opened. A malicious HTML page can be crafted that will execute code when loaded by Outlook Home Page. Once malicious home pages have been added to the user’s mailbox, they will be loaded when Outlook is started. Malicious Home Pages will execute when the right Outlook folder is loaded/reloaded.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN0502
Adversary uses a tool like Ruler to configure a malicious Outlook folder Home Page that loads a remote or embedded HTML payload upon folder interaction. Execution chain begins with Outlook launching, a specific folder being accessed, and a suspicious child process being spawned or COM-based execution invoked.
- AN0503
Malicious HTML or script is rendered as a Home Page for a specific Outlook folder. Outlook accesses that folder, loads remote content, and executes embedded JavaScript or ActiveX/COM logic resulting in unauthorized actions or local execution.
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