Win32/Virut [Threat Name] go to Threat

Win32/Virut.NBK [Threat Variant Name]

Category virus
Detection created Feb 02, 2009
Detection database version 10039
Aliases Virus.Win32.Virut.ce (Kaspersky)
  W32.Virut.CF (Symantec)
  W32/Virut.n (McAfee)
Short description

Win32/Virut.NBK is a polymorphic file infector. The virus connects to the IRC network. It can be controlled remotely.


The virus creates and runs a new thread with its own program code within the following processes:

  • winlogon.exe

The following Registry entries are created:

  • [HKEY_LOCAL_MACHINE\­SYSTEM\­CurrentControlSet\­Services\­SharedAccess\­Parameters\­FirewallPolicy\­StandardProfile\­AuthorizedApplications\­List]
    • "\­??\­%system%\­winlogon.exe" = "\­??\­%system%\­winlogon.exe:*:enabled:@shell32.dll,-1"

The performed data entry creates an exception in the Windows Firewall program.

Executable file infection

The virus searches for executables with one of the following extensions:

  • .exe
  • .scr

Executables are infected by appending the code of the virus to the last section.

The host file is modified in a way that causes the virus to be executed prior to running the original code.

It avoids those with any of the following strings in their names:

  • WINC
  • WCUN
  • WC32
  • OTSP

It infects the following files:

  • *.htm
  • *.php
  • *.asp
  • *.html

The virus inserts a/an IFrame element with an URL link into the file.

Other information

The virus acquires data and commands from a remote computer or the Internet.

It communicates with the following servers using IRC protocol:


It can execute the following operations:

  • download files from a remote computer and/or the Internet
  • run executable files

The virus modifies the following file:

  • %system%\­drivers\­etc\­hosts

The virus writes the following entries to the file:


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