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

W32.Opaserv.J.Worm - Removal

Risk Level 2: Low

Discovered:
December 20, 2002
Updated:
February 13, 2007 11:56:26 AM
Type:
Worm
Systems Affected:
Windows
CVE References:
CVE-2000-0979


IMPORTANTREAD THIS FIRST:
    • This worm uses a security vulnerability in Microsoft Windows 95/98/Me. It sends single-character passwords to network shares to get access to Windows 95/98/Me file shares, without knowing the entire password assigned to the shares. The affected systems include Windows 95, 98, and Me.

      A patch for computers running these operating systems can be found at http://www.microsoft.com/technet/security/bulletin/MS00-072.asp. If you have not already done so, obtain and install the patch to prevent future infections.
    • If you are on a network, or if you have a full-time connection to the Internet, such as DSL or cable modem, disconnect the computer from the network and the Internet. Disable sharing before you reconnect computers to the network or to the Internet. Because this worm spreads by using shared folders on networked computers, to ensure that the worm does not re-infect the computer after it has been removed, remove all he tshares, clean all the computers on the network, patch all the systems, and update the definitions on all the computers before you reconnect to the network or re-enable shares. For instructions on how to do this, see your Windows documentation or the document How to configure shared Windows folders for maximum network protection.
    • If you are removing an infection on a network, first make sure any shares are disabled.


Removal using the W32.Opaserv.Worm Removal Tool
This is the easiest way to remove this threat. Symantec Security Response has created a W32.Opaserv.Worm Removal Tool. Click here to obtain the tool. This removal tool can removal all discovered variants of W32.Opaserv.Worm through W32.Opaserv.K.Worm.


Manual Removal
As an alternative to using the removal tool, you can remove this threat manually. These instructions are for all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.
  1. Disconnect from the network.
  2. Update the virus definitions.
  3. Restart the machine in Safe mode.
  4. Run a full system scan and delete all the files detected as W32.Opaserv.J.Worm.
  5. If any files are found, delete the values

    Srv32 C:\WINDOWS\Srv32.exe
    Srv32Old <Path\original worm name>

    from the registry key

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
  6. For Windows 95/98/Me only, delete the line

    run=c:\Windows\Srv32.exe

    from C:\Windows\Win.ini, if this line exists.
For details on how to do this, read the following instructions.

To disconnect from the network:
If you are on a network, or if you have a full-time connection to the Internet, such as DSL or cable modem, disconnect the computer from the network and the Internet. Disable sharing before reconnecting computers to the network or to the Internet. Because this worm spreads by using shared folders on networked computers, to ensure that the worm does not re-infect the computer after it has been removed, remove all the shares, clean all the computers on the network, patch all the systems, and update the definitions on all the computers before you reconnect to the network or re-enable shares. For instructions on how to do this, see your Windows documentation or the document How to configure shared Windows folders for maximum network protection.

IMPORTANT—Do not skip this step:
  • Disconnect from the network before attempting to remove this worm.
  • For additional information on file sharing, read your Windows documentation or the document How to configure shared Windows folders for maximum network protection.
  • 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. Instead, share specific folders. These shared folders 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

    http://www.microsoft.com/technet/security/bulletin/MS00-072.asp.


To update the virus definitions:
All virus definitions receive full quality assurance testing by Symantec Security Response before being posted to our servers. There are two ways to obtain the most recent virus definitions:
  • Run LiveUpdate, which is the easiest way to obtain virus definitions. These virus definitions are posted to the LiveUpdate servers once a week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, look at the Virus Definitions (LiveUpdate) line at the top of this writeup.
  • Download the definitions using the Intelligent Updater. Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). They must be downloaded from the Symantec Security Response Web site and manually installed. To determine whether definitions for this threat are available by the Intelligent Updater, look at the Virus Definitions (Intelligent Updater) line at the top of this writeup.

    Intelligent Updater virus definitions are available here. For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, click here.

To scan for and delete the infected files:
  1. Start your Symantec antivirus program, and make sure that it is configured to scan all the files.
  2. Run a full system scan.
  3. If any files are detected as infected with the W32.Opaserv.J.Worm, click Delete.

To remove the value that the worm added to the registry:

CAUTION: Symantec strongly recommends that you back up the registry before you make any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify only the specified keys. Read the document How to make a backup of the Windows registry for instructions.
  1. Click Start, and then click Run. The Run dialog box appears.
  2. Type regedit, and then click OK. The Registry Editor opens.
  3. Navigate to the key

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
  4. In the right pane, delete these value:

    Srv32 C:\WINDOWS\Srv32.exe
    Srv32Old <Path\original worm name>
  5. Exit the Registry Editor.

To delete the line that the worm added to the Win.ini file:
This is necessary only on Windows 95/98/Me-based computers.

NOTE: For Windows Me users only. Due to the file-protection process in Windows Me, a backup copy of the file you are to edit exists in the C:\Windows\Recent folder. Symantec recommends that you delete this file before you continue with the steps in this section. To do this using Windows Explorer, go to C:\Windows\Recent, and in the right pane select the Win.ini file and delete it. It will be regenerated as a copy of the file you are to edit when you save your changes to that particular file.
  1. Click Start, and then click Run.
  2. Type the following, and then click OK.

    edit c:\windows\win.ini

    The MS-DOS Editor opens.

    NOTE: If Windows is installed in a different location, make the appropriate path substitution.
  3. In the [windows] section of the file, look for an entry similar to

    run=C:\WINDOWS\Srv32.exe
  4. Select the entire line. Be sure that you have not selected any other text in the file. Then press Delete.
  5. Click File, then click Save.
  6. Click File, then click Exit.


Writeup By: Yana Liu

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