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  3. Backdoor.Matsnu.B


Risk Level 1: Very Low

April 17, 2013
June 6, 2013 11:52:14 AM
Also Known As:
Trojan.Ransomlock.P [Symantec]
Infection Length:
Between 31,923 bytes and 164,864 bytes
Systems Affected:
Windows 2000, Windows 7, Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows Server 2008, Windows Vista, Windows XP
Backdoor.Matsnu.B is a Trojan horse that opens a back door on the compromised computer.

Note: Virus definitions dated April 17, 2013 or earlier may detect this threat as Trojan.Ransomlock.P.

Antivirus Protection Dates

  • Initial Rapid Release version April 17, 2013 revision 038
  • Latest Rapid Release version May 1, 2015 revision 037
  • Initial Daily Certified version April 18, 2013 revision 005
  • Latest Daily Certified version May 2, 2015 revision 001
  • Initial Weekly Certified release date April 24, 2013
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Threat Assessment


  • Wild Level: Low
  • Number of Infections: 0 - 49
  • Number of Sites: 0 - 2
  • Geographical Distribution: Low
  • Threat Containment: Easy
  • Removal: Easy


  • Damage Level: High
  • Payload: Opens a back door on the compromised computer.
  • Deletes Files: May delete the contents of the hard drive.


  • Distribution Level: Low
Note: On May 14, 2015, modifications will be made to the threat write-ups to streamline the content. The Threat Assessment section will no longer be published as this section is no longer relevant to today's threat landscape. The Risk Level will continue to be the main threat risk assessment indicator.
Writeup By: Masaki Suenaga

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