1. Symantec/
  2. Security Response/
  3. W32.Opaserv.AE.Worm


Risk Level 1: Very Low

January 7, 2004
February 13, 2007 12:15:51 PM
Systems Affected:

W32.Opaserv.AE.Worm is a variant of W32.Opaserv.Worm. It is a network-aware worm that spreads across open network shares. It copies itself to the remote computer as the file Natal.scr. The worm is packed with PEPACK.

This worm attempts to download updates from www.4ws.com.br, although the site may have already been shut down. Indicators of infection include:
  • The existence of the files, Putz!!!, Troxxx, Troxxx.dat, or Trossss.gay in %Windir%. This indicates a local infection (that is, the worm was executed on the local computer).
  • The existence of the file lammer! in the root of drive C. This may indicate a remote infection (that is, a remote host infected the computer).
  • The registry key HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run contains the string value Natal or Natal!Old, which is set to %Windir%\Natal.scr.

  • When the worm runs on Windows 95/98/Me-based computers, the worm can spread to other Windows 95/98/Me/2000/NT/XP-based computers through open network shares, but the worm cannot run on Windows 2000/NT/XP.
  • If you are on a network, or have a full-time connection to the Internet, such as DSL or Cable modem, disconnect the computer from the network and the Internet before attempting to remove this worm. If you have shared files or folders, disable them. When you have finished the removal procedure, if you decide to re-enable file sharing, Symantec suggests that you do not share the root of drive C. Share specific folders instead. These shares must be password-protected with a secure password. Do not use a blank password.

    Also, before doing so, if you are using Windows 95/98/Me, download and install the Microsoft patch from:

  • Virus definitions dated January 8, 2004 detect this as W32.Opaserv.Worm.

Antivirus Protection Dates

  • Initial Rapid Release version January 8, 2004
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version January 8, 2004
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date January 14, 2004
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
Writeup By: Fergal Ladley

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