W32/Phobos.3257!tr.ransom is a generic detection for a Ransomware Phobos 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%\info.hta : This is an HTA file and will serve as ransom note.
    • %Desktop%\info.txt : This is a text file and will serve as ransom note.
  • This malware was also observed to affect/encrypt files located on shared drives within the same subnet.
  • This malware was also observed to delete shadow copies by using Microsoft WMIC program.
  • Affected victims of this Ransomware are redirected by the attacker via:
  • Affected files of this Ransomware will use the filenaming format[ID].[Email].Extension, where italic strings are replaced.
  • Below are the file extensions and email addresses:
    • Extensions:
      • .acute
    • Email addresses:
  • This malware may apply any of the following registry modification(s):
    • HKCU\Software\Microsoft\Windows\Currentversion\Run
      • [OriginalMalware].exe = %Appdata%\Local\[OriginalMalware].exe
      This automatically executes the Ransomware every time the infected user logs on.
  • Below is an illustration of the malware's ransom notes:
    • Figure 1: Ransom note.
    • Figure 2: Ransom note.

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.