VBS.Godzilla.A@m

SUMMARY

VBS.Godzilla.A@m is very similar to WScript.KakWorm. This worm spreads using Microsoft Outlook Express. It attaches itself to all outgoing messages using the Signature feature of Outlook Express and Internet Explorer newsgroup reader.

The worm utilizes a known Microsoft Outlook Express security hole so that the viral files Update.hta and Sign.html are created on the system without having to run any attachment. Simply reading the received email message causes the virus to be placed on the system.

Protection

• Virus Definitions (Intelligent Updater) November 6, 2000

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 3 - 9
• Geographical Distribution: Low
• Threat Containment: Moderate
• Removal: Moderate

Damage

• Damage Level: Low
• Payload Trigger: October 10th
• Payload: Displays message
• Modifies Files: System registry

Distribution

• Distribution Level: Low
• Target of Infection: Microsoft Outlook Express, Internet Explorer Usenet Newsreader

TECHNICAL DETAILS

The worm appends itself to the end of legitimate outgoing messages as a signature. When receiving the message, the worm automatically creates a copy of itself in the C:WindowsStart MenuProgramsStartUp folder. Users who have Windows installed in a different path are not affected.

The worm utilizes a known Microsoft Outlook Express security hole, Scriptlet.Typelib, so that the viral files Update.hta and Sign.html are created on the system without having to run any attachment. Simply reading the email message causes the virus to be placed on the system.

Microsoft has patched this security hole. The patch is available on the Microsoft Web site. If you have a patched version of Outlook Express, the worm does not work automatically.

HTA files are executed by current versions of Microsoft Internet Explorer or Netscape Navigator. The system must be restarted for this file to be executed. Once executed, the worm obtains the Default User ID for Outlook Express and modifies the registry key

HKEY_CURRENT_USERIdentities{Default User ID}SoftwareMicrosoftOutlookExpress5.0Signatures

to add its own signature file, which is the infected Sign.html file. This causes all outgoing mail and newsgroup messages to be appended with the worm.

Finally, if the date is October 10, the following message is displayed after the computer starts:

Have you danced with the devil in the moonlight?

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 the VBS.Godzilla.A@m virus:

1. Delete the Update.hta and Sign.html files.
2. Reset your Outlook Express signature or remove the one that has been added. You can run Regedit.exe to modify the registry.
3. Delete the value of Default Signature in the following registry key:
   
   HKEY_CURRENT_USERIdentities{Default User ID}SoftwareMicrosoftOutlook Express5.0Signatures
   
4. Remove the entire 0000123 key.
5. Reset your signature by running Outlook Express.