X97M.Barisada.F

SUMMARY

This Microsoft Excel macro virus is a variant of X97M.Barisada.C. However, the payload has been removed. X97M.Barisada.F inserts a file in the Excel start directory called Khm.xls. The replication routine is triggered when a spreadsheet window is closed or deactivated.

Protection

• Virus Definitions (Intelligent Updater) September 1, 2000

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
• Payload Trigger: There is no payload for this variant of X97M.Barisada.

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

This macro virus inserts itself into every sheet of an active spreadsheet. The replication routine is triggered when a spreadsheet is deactivated or closed. The virus attempts to create a file called Khm.xls in the Excel start directory (usually OfficeXLSTART). The virus does not contain the same payload as the other variants. It does not change any options in Microsoft Excel.

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

Delete Khm.xls from the Microsoft Excel start directory. Clean all found infections