Discovered: December 13, 2000
Updated: February 13, 2007 11:46:41 AM
VBS.Forgotten.A@mm is a Visual Basic Script worm. Like many other worms, it uses Microsoft Outlook, mIRC, and Pirch to spread itself. The worm does not spread as an attachment within Outlook but as an HTML-formatted email that requires the user to enable ActiveX to run its code. Any .vbs and .vbe files are overwritten with a copy of the worm.
Antivirus Protection Dates
- Initial Rapid Release version January 11, 2001
- Latest Rapid Release version August 08, 2016 revision 023
- Initial Daily Certified version January 11, 2001
- Latest Daily Certified version August 09, 2016 revision 001
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
When executed, the VBS.Forgotten.A@mm worm performs the following actions:
- Copies itself to the Windows System directory as vb1.com.vbs.
- Searches for the mIRC program directory. If present, the worm overwrites the Script.ini file to spread itself when connected to mIRC.
- Searches for the Pirch program directory. If present, the worm overwrites the Events.ini file to spread itself when connected to Pirch.
- Sends a single email message to each address list found in Outlook, with each address entry added as a BCC address.
- Searches for .vbs and .vbe files on mapped drives, shared drives, and floppy disk drives in which disks are present. Overwrites these files with a copy of itself.
- Adds the value vb1 to the registry key HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run to enable itself at startup.
The worm also keeps a record of its infection by creating the registry key HKEY_CURRENT_USER\Software\(ANSWER). In this key, it stores information after it attempts to mail itself using Outlook. It also records whether it has affected the mIRC or Pirch programs. These actions are marked by the values "mailed," "mirqued," and "pirched" being created and set to 1. This lets the worm perform a check for previous infections.
Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":
- Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
- 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.
- Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
- Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
- Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
- Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
- If a 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.
- Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
- Isolate compromised computers quickly to prevent threats from spreading further. 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.
- If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
- For further information on the terms used in this document, please refer to the Security Response glossary.
To remove this worm:
- Run a full system scan, making sure that Norton AntiVirus is set to scan all files.
- Delete any file detected as infected with VBS.Forgotten.A@mm. These files cannot be repaired, and must be restored from clean backup copies.
- Using Registry Editor, select the following registry key:
- In the right pane, delete the following value:
- Delete the following registry key:
Writeup By: Brian Ewell