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05 March 2001
13 February 2007
Also Known As:

VBS.Vierika@mm is a worm that emails itself to all addresses in the Outlook address book with the following email attributes:

Subject: Vierika is here
Body text: Vierika.jpg
Attachment: Vierika.JPG.vbs

Antivirus Protection Dates

  • Initial Rapid Release version 05 March 2001
  • Latest Rapid Release version 28 September 2010 revision 054
  • Initial Daily Certified version 05 March 2001
  • Latest Daily Certified version 28 September 2010 revision 036
  • Initial Weekly Certified release date pending
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

VBS.Vierika@mm consists of 2 components (files). A VBS file and a HTML file.

The VBS file changes the Internet Explorer security settings so that it can freely execute the HTML component after it is loaded from a remote site. The VBS file also changes the Start Page of Internet Explorer to set it to an Italian URL. This URL contains the second component, the HTML file that contains the actual worm code.

When the HTML file is run, it first sets the Internet Explorer Start Page to the Italian URL so that it gets run again the next time Internet Explorer is started.
Second, the HTML file inserts a contaminated VBS file at C:\Vierika.JPG.vbs.
Finally, the HTML file emails itself to all address entries in all the address lists of the Outlook address book with the following email details:
  • Subject:
    Vierika is here
  • Body text:
  • Attachment:


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.

Delete any files detected as VBS.Vierika@mm and restore the proper security settings on Internet Explorer.
Writeup By: Andre Post