Threat Description

Trojan:​W32/DatCrypt

Details

Aliases: Trojan:​W32/DatCrypt, Gen:Trojan.Heur.mqW@vrF6mAoix, Trojan.Win32.Pincav.nms, Trojan.Xrupter (Symantec) , Generic.dx!jkx trojan (McAfee)
Category: Malware
Type: Trojan
Platform: W32

Summary



Also known as a trojan horse program, this is a deceptive program that performs additional actions without the user's knowledge or permission. It does not replicate.



Removal



Automatic Disinfection

Allow F-Secure Anti-Virus to disinfect the relevant files.

For more general information on disinfection, please see Removal Instructions.



Technical Details



Trojan:W32/DatCrypt drops a DLL file that encrypts files with specific extensions on the system. The DLL then informs the user that the affected files should be decrypted with a certain "utility program", which it also attempts to download and install on the system.A malware that engages in this type of behavior is known as Ransomware.

Execution

The DLL file is installed in the system32 folder with a random name. While active, the DLL searches the hard drive for files with the following extensions:

  • ppsm
  • ppsx
  • ppam
  • potm
  • potx
  • pptm
  • pptx
  • xlam
  • xlsb
  • xltm
  • xltx
  • xlsm
  • xlsx
  • dotm
  • dotx
  • docm
  • docx
  • ppt
  • xls
  • doc
  • pst
  • mdb
  • wma
  • mp3
  • png
  • jpeg
  • jpg
  • pdf

Many of these extensions are for Microsoft Office documents; the others are common media formats.Files found are encrypted. The program then displays a message when the user clicks the encrypted file, informing them the file is 'corrupted':

Download

The DLL will display a system notification message related to the supposed file corruption:

When clicked, the message initiates a download of a "utility program" for decrypting the affected files. The download is from

  • http://datahelpercorp.com/[...].exe

The downloaded utility program is detected as Rogue:W32/DatDoc.






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