Blocking macro-enabled Office files (docm, xlsm, etc)

[gleduc]

The available file types that can be filtered doesn't include Office documents with macros (docm, xlsm, etc).  These are being used now to sneak garbage into the network.  Is there a way to ID them or are they on the horizon for inclusion in the file blocking filters?  An innovative way that is being used is to create an xlsm file with a malicious macro in it and then replace the xlsm extension with csv.  User thinks it's just rows of text and clicks on it, Windows feeds it to Excel, and Excel opens it and runs the macro.

Gene

[reaper]

Hi Gene

In fileblocking the firewall is not able to differentiate doc files with or without macros as they are basically the same file type, it will be able to identify doc files 'disguised' as CSV as it looks deeper into the file than merely the extention . You could block doc files altogether, which may be a bit over the top.

Vulnerability protection has an ID for Office files containing Macros as BPry mentions

[Raido_Rattameister]

Block macros with GPO.

https://blogs.technet.microsoft.com/mmpc/2016/03/22/new-feature-in-office-2016-can-block-macros-and-...

[BPry · Accepted solution]

You can also block id 39154 which is Microsoft Office File with Macros. Please note that this isn't a perfect signature by far, but it does manage to take care of a good percentage of files before they hit our Barracudas 

[steveo]

Or Subscribe to Wildfire, it does a pretty bang up job with handling them!

Good luck!

-sO