1. Symantec/
  2. Security Response/
  3. W97M.Prilissa.A

W97M.Prilissa.A

Risk Level 2: Low

Discovered:
November 19, 1999
Updated:
February 13, 2007 11:33:40 AM
Also Known As:
W97M.Melissa.W, W97M.Prilissa.A
Type:
Macro

This is another variant of the Melissa virus. Because of the unknown-virus-and-variant detection technology in Norton AntiVirus, the current virus definitions will detect this new virus as W97M.AntiSocial.G. This technology allows Norton AntiVirus users to detect and repair W97M.Pri.Q without having a signature for this specific virus. Symantec AntiVirus Research Center will update the virus definitions to detect this virus as W97M.Pri.Q in the future virus definition files.

When an infected document is opened, the virus disables virus protection security settings, conversion confirmation, and the recently-opened-file list. The first time the virus is executed on a system, it sends email using Microsoft Outlook to the first 50 addresses in each of the address lists. The message contains "Message From {username}" in the subject line where {username} is the user name on the system. The body of the message contains "This document is very Important and you've GOT to read this !!!" The infected document is sent as an attachment to the message. The virus modifies the Windows registry so that it does not send email upon subsequent execution of the virus.

Next, the virus checks the date on the system to trigger its payload. On Dec. 25, the following text appears in a message box:

    ©1999 - CyberNET

    Vine...Vide...Vice...Moslem Power Never End...
    You Dare Rise Against Me... The Human
    Era is Over, The CyberNET Era Has
    Come !!!

Then, the virus copies itself to the global template, Normal.dot. Once, Normal.dot is infected, the virus infects documents when the file is closed from Word. It also disables the Macro command on the Tools menu so that the viral macros are hidden.

Some of the variable and function names in the viral code change upon replication. The virus keeps a list of labels in its code. Upon infection, the virus randomly changes each of the labels to another label in the list.

On December 25, several payloads are triggered. The virus displays the message box mentioned previously. It also overlays several colored shapes onto the currently open document. In addition, it overwrites the Autoexec.bat to format drive C and display the following text upon the next reboot of the system:

    Vine...Vide...Vice...Moslem Power Never End...
    Your Computer Have Just Been
    Terminated By -= CyberNET =- Virus !!!

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.
Writeup By: Wason Han
Summary| Technical Details

Search Threats

Search by name
Example: W32.Beagle.AG@mm
STAR Antimalware Protection Technologies
2016 Internet Security Threat Report, Volume 21
  • Twitter
  • Facebook
  • LinkedIn
  • Google+
  • YouTube