X97M.Barisada.C

SUMMARY

This Microsoft Excel macro virus replicates when an infected spreadsheet window is closed or deactivated. When the date is April 24th and the time is 14:00 (2PM), the virus prompts you to answer two questions or it threatens to delete the current spreadsheet. However, the viral payload does not work as intended

Protection

• Virus Definitions (Intelligent Updater) August 16, 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: When the date is April 24th and the time is 14:00 (2PM)
• Payload: The virus intends to delete the active Excel spreadsheet
• Modifies Files: Copies itself as Khm.xls in the Excel start directory

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

This variant of X97M.Barisada infects Microsoft Excel spreadsheets. The virus adds its viral macro module to every worksheet in the spreadsheet file. Once the virus is executed, it searches for the file Khm.xls in the Excel start directory. If the file is not found, the virus creates it.

The virus triggers a routine intended to delete the currently opened Excel file on April 24th at 14:00 (2PM). You are required to answer one or two yes-or-no questions.

The first question is:

What is the Sword Which Karl Styner(=Gray Scavenger) used?

Answer: Barisada.

The answer to this question is no. If you answer incorrectly, you are given one more opportunity to prevent the virus payload from triggering.

The second question is:

Summoning Xavier is the Ultimate Magic. Right?

The answer to this question is yes. Answering either question correctly prevents the virus from attempting to delete the currently opened Excel file. As previously noted, however, this function of the macro virus does not work as intended. The currently opened spreadsheet is cleared, but if you exit Microsoft Excel without saving the file, the data in the spreadsheet does not get removed.

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

Repair all found infections.

In the Excel start directory (usually OfficeXLSTART), repair or delete Khm.xls.