W32.Matcher.Worm

SUMMARY

W32.Matcher is an executable that arrives by email. When executed, the worm will email itself to everyone in the Microsoft Outlook Address book. The worm will continue to send emails while the process is running in the background.

Protection

• Virus Definitions (Intelligent Updater) April 18, 2001

Threat Assessment

Wild

• Wild Level: Medium
• Number of Infections: More than 1000
• Number of Sites: More than 10
• Geographical Distribution: High
• Threat Containment: Easy
• Removal: Easy

Damage

• Damage Level: Low

Distribution

• Distribution Level: High
• Subject of Email: Matcher
• Name of Attachment: Matcher.exe
• Size of Attachment: 28,672

TECHNICAL DETAILS

W32.Matcher is an email worm that arrives as:

Subject: Matcher

Message: Want to find your love mates!!! Try this its cool... Looks and Attitude Maching to opposite sex.

When executed, the worm does the following:

1. Copies itself to the WindowsSystem folder as Matcher.exe.
2. Next, the worm adds the following value:
   
   (Default)    <WindowsSystem folder> Matcher.exe
   
   to the registry key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoft
   WindowsCurrentVersionRun
   
   This will execute the worm when Windows starts.
   
3. The worm then sends itself to everyone in the Outlook Address book with the previously mentioned email. The worm will continue to send emails in an infinite loop.
4. The worm also modifies the C:Autoexec.bat file, and appends the lines:
   
   @echo off
   echo from: Bugger
   pause

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

To remove this worm, delete all detected files, remove the entry that it made to the registry Run key, and delete the entry that it made to the Autoexec.bat file.

To remove this worm:

1. Run LiveUpdate to make sure that you have the most recent virus definitions.
2. Start Norton AntiVirus (NAV), and then run a full system scan, making sure that NAV is set to scan all files.
3. Delete any files detected as W32.Matcher

To edit the registry:

CAUTION: We strongly recommend that you back up the system registry before making any changes. Incorrect changes to the registry could result in permanent data loss or corrupted files. Please make sure you modify only the keys specified. Please see the document How to back up the Windows registry before proceeding.

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 following subkey:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoft
   WindowsCurrentVersionRun
   
   
4. In the right pane, delete the following value:
   
   (Default)    <WindowsSystem folder> Matcher.exe
   
5. Click Registry and then click Exit to save the changes.

To edit the Autoexec.bat file:

1. Click Start and then click Run.
2. Type the following and then press Enter:
   
   edit c:autoexec.bat
   
3. Locate the following lines and delete them:
   
   @echo off
   echo from: Bugger
   pause
   
4. Click File and then click Save.
5. Click File and then click Exit.