Win32/Gyimface [Threat Name] go to Threat

Win32/Gyimface.A [Threat Variant Name]

Category worm
Size 126976 B
Detection created Feb 01, 2012
Detection database version 6847
Aliases Trojan.Win32.Buzus.ktdc (Kaspersky)
  Worm:Win32/Stekct.A (Microsoft)
  W32/Checkout!bc.virus (McAfee)
Short description

Win32/Gyimface.A is a worm that spreads via IM networks.


When executed, the worm copies itself in some of the the following locations:

  • %windir%\­mdm.exe
  • %programfiles%\­mdm.exe
  • %public%\­mdm.exe

In order to be executed on every system start, the worm sets the following Registry entries:

  • [HKEY_LOCAL_MACHINE\­SOFTWARE\­Microsoft\­Windows\­CurrentVersion\­Run]
    • "Microsoft Firevall Engine" = "%malwarefilepath%"
  • [HKEY_CURRENT_USER\­SOFTWARE\­Microsoft\­Windows\­CurrentVersion\­Run]
    • "Microsoft Firevall Engine" = "%malwarefilepath%"
  • [HKEY_LOCAL_MACHINE\­SOFTWARE\­Microsoft\­Windows NT\­CurrentVersion\­Terminal Server\­Install\­Software\­Microsoft\­Windows\­CurrentVersion\­Run]
    • "Microsoft Firevall Engine" = "%malwarefilepath%"

The worm executes the following command:

  • netsh firewall add allowedprogram "%malwarefilepath%" "MSN Messenger" ENABLE

The performed command creates an exception in the Windows Firewall.

The following Registry entry is set:

  • [HKEY_LOCAL_MACHINE\­SYSTEM\­CurrentControlSet\­Services\­SharedAccess\­Parameters\­FirewallPolicy\­StandardProfile\­AuthorizedApplications\­List]
    • "%malwarefilepath%" = "%malwarefilepath%:*:Enabled:Microsoft Firevall Engine"

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

Spreading via IM networks

Win32/Gyimface.A is a worm that spreads via IM networks.

The worm spreads through links which point to websites containing malware.

The following services are affected:

  • MSN Messenger
  • Skype
  • Google Talk Client
  • Yahoo Messenger
  • ICQ
  • AOL Instant Messenger
  • Pidgin
  • Facebook Chat
Other information

The worm acquires data and commands from a remote computer or the Internet. The worm contains an URL address.

It may perform the following actions:

  • download files from a remote computer and/or the Internet
  • run executable files
  • spread via IM networks

The following programs are terminated:

  • svhost.exe
  • YahooAUService.exe
  • ekrn.exe
  • egui.exe
  • msseces.exe

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