OutlookToolbox

Hey all,

Lately I’ve been neglecting my CTF posts so I could put some time into OutlookToolbox, a C# DLL that uses COM to target Outlook in the background.  Additionally, I put together a Cobalt Strike Aggressor script to assist with the execution of OutlookToolbox,  both of which can be found at the repository here – https://github.com/ThunderGunExpress/OutlookToolbox.

This is a quick and dirty post which will cover the features.  Later, I plan on creating another post which further explores potential use cases of OutlookToolbox.

Mandatory

  • Only use for good.
  • I have not done extensive testing with this tool, use at your own risk. I recommend testing OutlookToolbox on a replica of your target first.
  • The Aggressor script uses several brm (file and/or directory remove) function calls which can bulldoze entire directories if input is not sanitized correctly. I’ve tried to iron out all the issues, but still, I would put OutlookToolbox in a non-critical directory like C:\Users\Public\Documents just to be safe.

What it Does

  • Lists folders in Outlook (Inbox, Sent Items, Conversation History, Joe’s Custom Folder … )
  • Exports target folder to a CSV File
  • Enumerate targets using the GAL
  • Download specific messages
  • Sends an email on behalf of the target user

How to Prevent

Configure Outlook’s programmatic access security to report on suspicious activity – MS link.  Email encryption will cause several of these functions not to work, not a bad idea.

oSecurity

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