VBS.Gorum.A@mm

SUMMARY

VBS.Gorum.A@mm is an encoded Visual Basic Script (VBE) worm. It arrives as the attachment STU-CMH.txt.vbe. Like many other worms, it uses Microsoft Outlook to spread. The worm deletes multiple files and folders from drives C through F.

Protection

• Virus Definitions (Intelligent Updater) April 23, 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: High

Distribution

• Distribution Level: High

TECHNICAL DETAILS

When the worm is executed, it does the following:

1. It copies itself to C: and to the WindowsSystem folder as STU-CMH.txt.vbe.
2. It changes the Microsoft Internet Explorer home page to http:/ /www.stu.edu.tw
3. It adds the value
   
   STU-CMH       <Windows System Folder>STU-CMH.txt.vbe
   
   to the registry key
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
   
   to enable itself to run at startup.
   
4. It drops the C:virus information.txt file with the following contents:
   
   **********************************************************************
   **********     The Virus Program Information                 **********
   **********     Designer :  VHacker                           **********
   **********     Place :  Taiwan                               **********
   **********     Create Date : 04/19/2001                      **********
   **********     Modification Time :04/19/2001                 **********
   ***********************************************************************
   
5. It sends an email message to all contacts in all address lists found in Microsoft Outlook. The email message is as follows:
   
   Subject: STU-CMH
   
   Message: School Name:SHU-TE Institute of Technology
   
   Attachment: STU-CMH.txt.vbe
   
6. The worm attempts to delete .mp3, .jpg, .jpeg, .bmp, .exe, and .zip files from the root of drive C, and all files and folders from the drives D, E, and F.
7. The worm also attempts to delete the following folders:
   C:Program FilesACD
   C:Program FilesTrend PC-cillin 98
   C:Program FilesMicrosoft Office97
   C:Program FilesNorton
   C:Program FilesWinZip
   C:Program Filesinamp
   C:Program FilesAdobe
   C:WindowsCOMMAND
   C:WindowsStart Menu
   C:WindowsFONTS
   C:My Documents

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 VBS.Gorum.A@mm, and undo the change that it made to the registry. Restore the Internet Explorer home page and missing files.

NOTE: If the worm has executed on Windows 95, 98 or Me, you may have to reinstall some programs or the operating system.

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 VBS.Gorum.A@mm.

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:
   
   STU-CMH       <Windows System Folder>STU-CMH.txt.vbe
   
5. Start Internet Explorer, and reset the home page to one of your preference.

Restore any deleted files and the start page
If the worm has run, you will need to restore missing files from a clean backup and reset the Internet Explorer home page to one of your choice.