JS.Disturbed.A@m

SUMMARY

JS.Disturbed.A@m is a worm that uses Microsoft Outlook and Outlook Express to spread itself. This worm inserts its code into every email message that you send.

Protection

• Virus Definitions (Intelligent Updater) May 4, 2001

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Easy

Damage

• Damage Level: Low
• Payload Trigger: If today is the 4th day of the month or earlier
• Payload: Sets Internet Explorer start page to http://www.geocities.com/yamaperu/

Distribution

• Distribution Level: Medium
• Target of Infection: Outlook and Outlook Express email messages

TECHNICAL DETAILS

JS.Disturbed.A@m checks the registry to see if Microsoft Outlook or Outlook Express is the default email client. If either is the default, the worm modifies the registry so that its code is inserted into every email message that you send using either of the two clients.

To ensure that the worm is run when Windows starts, the worm adds the value

yama C:Program Filesyama.hta

to the key

HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun

If the date is prior to the 4th day of any month, the home page of Internet Explorer is set to http:/ /www.geocities.com/yamaperu/.

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 any files detected as JS.Disturbed.A@m, and undo the change that the worm made to the registry.

To remove the worm:

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

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 click Run. The Run dialog box appears.
2. Type regedit and then click OK. The Registry Editor opens.
3. Navigate to the following key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
   
4. In the right pane, delete the following value:
   
   yama   C:Program Filesyama.hta
   
5. Click Registry, and click Exit to save the changes.