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03 September 2002
13 February 2007
Also Known As:
Systems Affected:

VBS.Ednav@mm is a worm that uses Microsoft Outlook to distribute a copy of itself to all contacts in the Microsoft Outlook Address Book. The subject of the email message is "System Administrator Notification," and an infected .vbs file is attached.

Antivirus Protection Dates

  • Initial Rapid Release version 04 September 2002
  • Latest Rapid Release version 28 September 2010 revision 054
  • Initial Daily Certified version 04 September 2002
  • Latest Daily Certified version 28 September 2010 revision 036
  • Initial Weekly Certified release date 04 September 2002
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

When VBS.Ednav@mm runs, it does the following:

It displays this fake message:

The worm then overwrites all .vbs files in the C:\%windir%\Samples\WSH folder. Each time that the worm overwrites a .vbs file, it uses Microsoft Outlook to send the overwritten .vbs file to all contacts in the Outlook Address Book .

NOTE : %windir% is a variable. The worm locates the \Windows folder (by default this is C:\Windows or C:\Winnt) and searches the folder Samples\WSH in that location. If the C:\%windir%\Samples\WSH folder does not exist, or if there is no .vbs file in this folder, the worm does not spread.

The email message has the following characteristics:

Subject:  System Administrator Notification
Due to the recent problems with the email server, we have devised a program that will fix it up.                                                                                                            
You are requested to download the attached file and execute it at once. The whole setup will take 5 to 10 minutes. If your system crashes, just restart your computer and everything will be back to normal.

Please follow instructions carefully.
System Administrator
Network Management.
Attachment: <The infected .vbs file>

If the system date is the 1st, 30th, or 31st of the month, the worm deletes all files on the current user's Desktop.


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.

NOTE: These instructions are for all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

Update the virus definitions, run a full system scan, and delete all files that are detected asVBS.Ednav@mm. For details on how to do this, read the following instructions.

To update the virus definitions:
There are two ways to obtain the most recent virus definitions:
  • Run LiveUpdate, which is the easiest way to obtain virus definitions. These virus definitions have undergone full quality assurance testing by Symantec Security Response and are posted to the LiveUpdate servers one time each week (usually Wednesdays) unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, look at the Virus Definitions (LiveUpdate) line at the top of this write-up.
  • Download the definitions using the Intelligent Updater. Intelligent Updater virus definitions have undergone full quality assurance testing by Symantec Security Response. They are posted on U.S. business days (Monday through Friday). They must be downloaded from the Symantec Security Response Web site and installed manually. To determine whether definitions for this threat are available by the Intelligent Updater, look at the Virus Definitions (Intelligent Updater) line at the top of this write-up.

    Intelligent Updater virus definitions are available here. For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, click here.
To scan for and delete the infected files:
  1. Start your Symantec antivirus program, and make sure that it is configured to scan all files.
  2. Run a full system scan.
  3. If any files are detected as infected with VBS.Ednav@mm, click Delete.

NOTE: In most cases, you should not have to replace any overwritten files that were located in the C:\%windir%\Samples\WSH folder. By default they are, as the folder name suggests, only sample files.
Writeup By: Yana Liu