X97M.Fixen

SUMMARY

X97M.Fixen is a macro virus that infects Microsoft Excel workbooks. The viral code is inserted into a macro module named v123.

Protection

• Virus Definitions (LiveUpdate™ Weekly) May 1, 2002
• Virus Definitions (Intelligent Updater) May 1, 2002

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

X97M.Fixen is activated when you open an infected workbook. It then performs the following actions:

It creates these files:

• C:Program FilesMicrosoft OfficeOfficev123.vbs
• C:Program FilesMicrosoft OfficeOfficev123.xls
• C:v123.bas

NOTE: v123.vbs is detected as VBS.Fixen.

The virus then adds the value

v123

to the registry key

HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun

so that the virus runs each time that you start Windows.

The virus also changes the value data of several values in the registry key

HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersion

The changes are as follows:

Value Value Data
ProductName Microsoft Windows 0.1
RegisteredOrganization Completely no good system companyWindows 0.1
Version Number 0.00.0001
SystemRoot C:

NOTE: Because these values are in a different key in Windows NT/2000/XP, it is likely that these changes will not occur on these operating systems.

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. Delete all files that are detected as VBS.Fixen. Repair files that are detected as X97M.Fixen. Manually delete v123.bas.
3. Reverse the changes that the virus made to the registry.
   

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 once 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 delete the infected files:

1. Start your Symantec antivirus program, 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 VBS.Fixen, click Delete. If any files are detected as X97M.Fixen, click Repair.
4. Use Windows Explorer to locate and delete C:v123.bas.

To delete the value that the virus added to the registry:

CAUTION: Symantec strongly recommends that you back up the registry before you make any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify only the keys that are specified. Read the document How to make a backup of the Windows registry for instructions.

1. Click Start, and click Run. The Run dialog box appears.
2. Type regedit and then click OK. The Registry Editor opens.
3. Navigate to the key
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
4. In the right pane, delete the value
   
   v123
   
5. Navigate to the key
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersion
   
6. In the right pane, examine each of these values:
   
   ProductName
   RegisteredOrganization
   Version Number
   SystemRoot
   
7. If the virus changed any of the values, double-click them, and change the displayed text so that it shows the correct information.
8. Exit the Registry Editor.