W97M.Cheechoong.A

SUMMARY

W97M.Cheechoong.A is a very small macro virus that replicates using the Normal.dot template file. If the current day of the month is equal to the number of the current month, the Office Assistant displays a message.

Protection

• Virus Definitions (Intelligent Updater) October 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: If current day of the month is equal to the number of the current month
• Payload: The Office Assistant displays a message

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

W97M.Cheechoong.A activates on document open.

The virus first conceals its presence by switching off VirusProtection, SaveNormalPrompt, and ConfirmConversions.

It then attempts to infect the Normal.dot template file and the active document.

The payload is executed if the current day of the month is equal to the number of the current month. The Office Assistant appears with the following message:

Have a great CheeChoong...

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

Use Norton Antivirus to detect and repair infected files.