VBS.Crystal.C

SUMMARY

VBS.Crystal.C is a Visual Basic Script (VBS) worm that uses Pirch channels to spread and infect .vbs files.

Protection

• Virus Definitions (Intelligent Updater) March 22, 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: On the st or 20th of every month
• Payload: Displas a message.

Distribution

• Distribution Level: Low
• Name of Attachment: Crystal2.vbs
• Target of Infection: Pirch

TECHNICAL DETAILS

When VBS.Crystal.C is executed:

1. It creates the Events3.dll text file in the C:Windows folder.
2. It writes a Pirch script in the Events3.dll file to send itself to other users of Pirch.
3. It copies Events3.dll to C:Pirch98Events.ini and C:Pirch32Events.ini.
4. It copies itself to C:WindowsCrystal2.vbs.
5. It copies itself to C:WindowsStart menuProgramsStartUpStartup.vbs so that it runs at Windows startup.
6. It inserts its malicious code into .vbs files that are in the same folder as the worm and those that are located in:
   • C:Windows
   • C:WindowsDesktop
7. On the first or twentieth day of every month, the following message appears:
   
   The screams fill the room
   Alone I drop and kneel

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:

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. If any files are detected as infected by VBS.Crystal.C or VBS.Crystal.C.ini, click Delete.