MSIL/Crypren_V2_0!tr.ransom

Analysis

MSIL/Crypren_V2_0!tr.ransom is a generic detection for a Ransomware Crypren trojan. Since this is a generic detection, this malware may have varying behaviour.
Below are some of its observed characteristics/behaviours:

• This malware may drop any of the following file(s):
  
  • %Desktop%\#DECRYPT MY FILES#.txt: This file is a txt file and will serve as ransom notes.
  • %Desktop%\#解密我的文件#.txt: This file is a txt file and will serve as ransom notes in Chinese.
  • %Desktop%\#РАСШИФРОВЫВАТЬ МОИ ФАЙЛЫ#.TXT: This file is a txt file and will serve as ransom notes in Russian.
  • %Desktop%\WallPaper.bmp: This file is a picture and will serve as ransom notes.


• This malware was also observed to affect/encrypt files located on shared drive within the same subnet.


• This Ransomware also changes desktop background to ransom notes.


• Affected files of this Ransomware will use the prepending filenaming format as {Originalname.Ext}.[fileslocker@pm.me].


• This is a Crypren 2.0 version Ransomware which has the same characteristics/behaviours as other versions of Crypren. Generic description for Crypren: MSIL/Crypren.FA2A!tr.ransom.


• Below is illustrations of the malware's Ransom notes:
  

  Figure 1: Ransom notes.

  
  

Figure 2: Ransom notes.




Figure 3: Ransom notes.




Figure 4: Ransom notes.




Figure 5: Ransom notes.

Recommended Action

• Make sure that your FortiGate/FortiClient system is using the latest AV database.
• Quarantine/delete files that are detected and replace infected files with clean backup copies.