Suspicious files in Firefox Extension Folder

[User 13]

I found a suspicious file in the firefox extension folder on my PC and laptop.

 

I think it is a kind of malware, because it modifies the Firefox settings by injecting a user.js file that disables all firefox updates.

 

Here are the links to virustotal (currently only 1 AV detects it as malware):

 

https://www.virustotal.com/de/file/7aa0687cf536c94af1b3d68a91f7279e73d38dd8153da9c9e14161290e972752/analysis/1435932987/

 

https://www.virustotal.com/de/file/d6d4e4e406b506f94b27000b22309caaa60e795295571803c1a6bb86644c77df/analysis/

 

I also submitted the files to ESET and deleted them, but I don't know if they caused more harm, a full scan with ESS doesn't find anything.

Edited July 3, 2015 by User