VBS.Noon

SUMMARY

This is a typical VBS worm that uses Microsoft Outlook MAPI to mail itself out to all contacts in the email address book. One notable difference though lies in how this worm reacts to different mailer programs installed on the computer.

NOTE: The first sample of this worm the Symantec AntiVirus Research Center (SARC) received contained a bug that prevented it from replicating on any computer.

Protection

• Virus Definitions (Intelligent Updater) July 31, 2001

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Easy

Damage

• Damage Level: Low

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

Activation
When this worm is activated it deletes the file C:WindowsRundll32.exe. This path name is hardcoded in the virus. Depending on which email client you are using at the time, the virus will then do one of two things:

If you are using Microsoft Outlook
If you are using Outlook, this worm will create copies of itself on your C drive with the following names (the path and file names are hard-coded in the worm):

C:Wormmie.vbs
C:Wormmie.bat
C:Wormmie.ini
C:Wormmie.pif
C:Program FilesWormmie.vbs
C:My DocumentsWormmie.vbs

The virus also creates the following file in your WindowsSystem folder:

%System%Wormmie.vbs

NOTE: %System% is a variable which identifies the location of your WindowsSystem folder.

The file Wormmie.vbs is used by the worm to send itself out to all the contacts in your Microsoft Outlook Address Book. While going through your contact list, this worm displays a message box with the email address of each contact that is sent a copy of the worm. After emailing each contact, this worm will create the following registry key, which it sets to the value of 1:

HKEY_CURRENT_USERsoftwareAnmailed

If you are not using Microsoft Outlook
If you are using a email client other than Microsoft Outlook, this worm will display the following series of message boxes:.



If the registry key HKEY_CURRENT_USERsoftwareAnmailed is set to 1, the worm displays the following message box:



If the registry key HKEY_CURRENT_USERsoftwareAnmailed is not set to 1, the worm displays the following message box:



Finally the worm does a time check to see if the time is equal to 00:00:00 or 12:00:00. If the time is equal to 00:00:00 it displays the following message box:



If the time is equal to 12:00:00 the worm displays the following message box:



Message
Following the email program-dependent actions discussed prefiously, the worm opens one of three Internet search engines. Finally the worm displays a message box with the following text:

Wormmie
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!
Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie! Wormmie!

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended 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 (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. 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.

REMOVAL

1. Run LiveUpdate to make sure that you have the most recent virus definitions.
2. Start Norton AntiVirus (NAV), and run a full system scan. Be sure that NAV is set to scan all files.
3. Delete any files detected as VBS.Noon.