Threat Descriptons



Category :


Type :


Aliases :

Worm.Win32.Autorun.nds, Worm:Win32/Taterf.gen!C (Microsoft)


This worm propagates via the the mapped drives on the infected machine. It also attempts to steal login and account information for popular online games, as well as login details for Yahoo! email.


Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details


Upon detection, the worm drops a copy of itself in the root of all mapped drives from C: to Z:, including network drives. Any machine connected to an infected network drive will then be infected themselves when they access the drive. The worm also creates an autorun.inf file, which is used to execute the worm automatically when the root of the drive is viewed using Windows Explorer.The typical "autorun.inf" appears as:

[AutoRun] open=c.cmd shell\open\Command=c.cmd shell\open\Default=1 shell\explore\Command=c.cmd


The worm also creates a number of files, including the mmvo0.dll file which is detected as Trojan-PSW:W32/OnlineGames.TLB. This malware is used to obtain account information for popular online games such as Ragnorak Online.In addition, it attempts to capture Yahoo! email login details whenever the following URLs are accessed:


The captured information is most likely sent to the remote server.


Upon execution, the worm modifies a number of registry keys in order to thwart recognition and removal. If it detects the files No32Kui.exe (NOD32 Antivirus) and RavMon.exe (RAV Antivirus), it will attempt to terminate them to prevent these security products from detecting its presence. While the worm is making these registry changes, it will also attempt to prevent NOD32 Antivirus from displaying alert notifications.

File System Changes

Creates these files:

  • %temp%\gm5d.dll
  • %windir%\system32\mmvo.exe
  • %windir%\system32\mmvo0.dll
  • c:\c.cmd
  • c:\autorun.inf

Modified these files:

  • %windir%\system32\drivers\vga.sys

Uses these temporary files:

  • c:\c.cmd
  • c:\autorun.inf
  • c:\c.cmd
  • c:\autorun.inf

Process Changes

Uses these temporary processes:

  • %programfiles%\Internet Explorer\IEXPLORE.EXE

These modules were loaded into other processes:

  • %windir%\system32\mmvo0.dll -> Loaded into C:\Windows\explorer.exe

Registry Modifications

Sets these values:

  • HKLM\System\CurrentControlSet\Services\KAVsys Type = 00000001
  • HKLM\System\CurrentControlSet\Services\KAVsys ErrorControl = 00000001
  • HKLM\System\CurrentControlSet\Services\KAVsys Start = 00000001
  • HKLM\System\CurrentControlSet\Services\KAVsys ImagePath = C:\WINDOWS\system32\drivers\vga.sys
  • HKCU\SoftWare\Microsoft\Windows\CurrentVersion\Run mmva = C:\WINDOWS\system32\mmvo.exe
  • HKCU\Software\Mircrosoft\Windows\CurrentVersion\Explorer\Advanced Hidden = 2
  • HKCU\Software\Microsoft\Windows\CurrentVErsion\Explorer\Advanced ShowSuperHidden = 0
  • HKLM\Software\Microsoft\Windows\CUrrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL CheckedValue = 0

Creates these keys:

  • HKLM\System\CurrentControlSet\Services\KAVsys
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