BAT.Copykaz.Worm

SUMMARY

BAT.Copykaz.Worm is a generic detection for simple batch file worms that spread through file-sharing networks. These worms propagate by copying themselves to the shared directories that file-sharing networks use, such as KaZaA, Morpheus, and Grokster.

Protection

• Virus Definitions (LiveUpdate™ Weekly) October 15, 2003
• Virus Definitions (Intelligent Updater) October 13, 2003

TECHNICAL DETAILS

A file detected as BAT.Copykaz.Worm will typically perform the following actions:

1. Copyies itself multiple times to the default shared folders that file-sharing programs use. Paths are usually hard-coded, and may include:
   
   • C:Program FilesKazaaMy Shared Folder
   • C:Program FilesKazaa LiteMy Shared Folder
   • C:Program FilesMorpheusMy Shared Folder
   • C:Program FilesGroksterMy Grokster
   • C:Program FilesBearShareShared
   • C:Program FileseDonkey2000Incoming
   • C:Program FilesICQShared Files
     
     
2. May attempt to set itself to run on startup, by adding an entry to one of the registry keys:
   
   • HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   • HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersion
     RunServices
   • HKEY_CURRENT_USERSOFTWAREMicrosoftWindowsCurrentVersionRun
     
     
3. May reconfigure file-sharing programs to use a different shared directory. This may depend on which program is installed.

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
• Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. Perform a forensic analysis and restore the computers using trusted media.
• Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.

REMOVAL

The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Disable System Restore (Windows Me/XP).
2. Update the virus definitions.
3. Run a full system scan and delete any files detected as BAT.Copykaz.Worm.
4. Reverse the changes that the worm made to the Registry.
5. Check the configuration of file-sharing programs

For specific details on each of these steps, read the following instructions.

1. Disabling System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:

• "How to disable or enable Windows Me System Restore"
• "How to turn off or turn on Windows XP System Restore"

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Note: When you are completely finished with the removal procedure and are satisfied that the threat has been removed, re-enable System Restore by following the instructions in the aforementioned documents.

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For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article, "Antivirus Tools Cannot Clean Infected Files in the _Restore Folder," Article ID: Q263455.

2. Updating the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:

• Running LiveUpdate, which is the easiest way to obtain virus definitions: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to the Virus Definitions (LiveUpdate).
• Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to the Virus Definitions (Intelligent Updater).
  
  The Intelligent Updater virus definitions are available: Read "How to update virus definition files using the Intelligent Updater" for detailed instructions.

3. Scanning for and deleting the infected files

1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
   • For Norton AntiVirus consumer products: Read the document, "How to configure Norton AntiVirus to scan all files."
   • For Symantec AntiVirus Enterprise products: Read the document, "How to verify that a Symantec Corporate antivirus product is set to scan all files."
2. Run a full system scan.
3. If any files are detected as infected with BAT.Copykaz.Worm, note the path and file name, and click Delete.

4. Reversing the changes made to the registry

CAUTION: Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified keys only. 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
   
   Then click OK. (The Registry Editor opens.)
   
   
3. Navigate to the keys:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   HKEY_CURRENT_USERSOFTWAREMicrosoftWindowsCurrentVersionRun
   
   
4. Refer to the list of infected files that you created while following the instructions in step c of the previous section, "Scanning for and deleting the infected files."
   
   In the right pane, look at the entries in the Name and Data columns. If you find an entry that refers to a file that was detected as infected, select the entry, press Delete, and then click Yes to confirm.
   
   
5. Do one of the following:
   • Windows NT/2000/XP: Skip to step g.
   • Windows 95/98/Me: Navigate to the key:
     
     HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRunServices
     
     
6. Refer to the list of infected files that you created while following the instructions in the previous section. In the right pane, look at the entries in the Name and Data columns. If you find an entry that refers to a file that was detected as infected, select the entry, press Delete, and then click Yes to confirm.
   
   
7. Exit the Registry Editor.

5. Checking the configuration of file-sharing programs

Some worms may change the settings of the file-sharing programs, typically by adding a new shared folder that contains the worm. In this case, you will have to reconfigure the software to point to the actual location of your shared files and remove the references to any folders that the worm added. Consult the documentation for your file-sharing program for more information on completing this process.