Threat Explorer

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VBS.Jer(htm)

VBS.Jer(htm)

Updated:
13 February 2007

This worm appears as the attachment Jer.htm. Opening the attachment in your Internet browser displays a page that contains "The 40 Ways Women Fail in Bed". This is meant to serve as a distraction while the worm does its work in the background. There is a script embedded within the .htm file that allows the worm to spread itself via MS Outlook and mIRC.

Antivirus Protection Dates

  • Initial Rapid Release version 06 July 2000
  • Latest Rapid Release version 08 August 2016 revision 023
  • Initial Daily Certified version 06 July 2000
  • Latest Daily Certified version 09 August 2016 revision 001
  • Initial Weekly Certified release date pending
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

The VBS.Jer(htm) script-worm is based on VBS.LoveLetter. This worm is embedded within a .htm file. It propagates by mass-mailing through MS Outlook and through a file transfer in mIRC. This worm modifies the registry key
    HKLM\Software\Microsoft\Windows\CurrentVersion\Run

by adding the value "GinSenG" and setting it equal to the location of the Jer.htm file. This file gets created in your Windows system directory. Modifying the aforementioned registry key allows the worm to enable itself when the computer restarts.

The worm also modifies the following registry keys to disable certain functions of the OS:
    HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\NoFind is set to "1".
    HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\NoDesktop is set to "1".
    HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\NoClose is set to "1".
    HKLM\Software\Microsoft\Windows\CurrentVersion\Version is set to "VBS.GinSenG".
    HKLM\Software\Microsoft\Windows\CurrentVersion\RegisteredOwner is set to "I Love You, Min".
    HKLM\Software\Microsoft\Windows\CurrentVersion\RegisteredOrganization is set to "GinsengBoy 2000".
    HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Network\NoNetSetup is set to "1".

This corresponds to the following effects:
  • The Find function is not accessible.
  • All icons are disabled and no longer appear on the desktop.
  • The user is prevented from shutting down the computer through the Start menu. The computer must be powered off, reset, or shut down by pressing Ctrl+Alt+Del and then selecting shut down.
  • The Version and RegisteredOwner/Organization keys do not have an adverse affect on the system. These keys modify the data that can be seen when the System Properties are displayed.
  • Access to Network Properties is disabled on Windows98 computers.

Recommendations

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.