X97M.BDoc2

SUMMARY

X97M.BDoc2 is a Excel macro virus that infects the active workbook and inserts an infected workbook in the XLStart folder.

Protection

• Virus Definitions (Intelligent Updater) August 1, 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
This virus is activated when opening, closing, or saving a file, and when Excel starts or exits. However, it only infects workbooks when files are opened, closed, or saved.

When this virus is activated, it disables:

• Macro virus protection in Excel.
• The display of alerts when a modified workbook is saved.
• Screen updating. The modifications are not displayed; this is done to hide its activities.

The virus infects the active worksheet by creating the module Bdoc2, into which it inserts itself.

Insertion
This virus also inserts the infected file AutoRun.xls into the XLStart folder so that it will be executed when Excel starts.

Payload
This virus tries to disable the Macro command on the Tools menu, but it uses a hardcoded string value which works only in a specific Asian version of Excel.

On exit
If the day is the 26th of the month, this virus displays a message in an Asian language. If the day of the month is the 5th, 10th, 15th, 25th or 30th, it causes Windows to shut down.

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 configured to scan all files.
3. If any files are detected as infected by X97M.BDoc2, click Repair.