W97M.MMKV

SUMMARY

W97M.MMKV is part of a family of simple macro viruses that use January 1st, 2000 as the malicious-payload trigger date. There are three known variants of this macro virus. They are described in detail below.

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

The infection routine cannot infect documents in the SR-1 version of MS Word 97. Otherwise, it infects documents on the opening and saving activities.

The infection routine of this virus is very ordinary. Bloodhound heuristic easily detects this macro virus.

Payload

Upon opening an infected file or launching an infected MS Word, the virus checks for the date. If the year is 2000, it activates the malicious payload:

· Variant A: deletes all files from the current directory and C:
· Variant B: inserts a malicious program file named C:END.COM to overwrite parts of the hard drive partition
· Variant C: inserts the same program file as Variant B, but the name is changed to C:END.A. This effectively disables the payload

After the malicious activity, it displays a message box entitled:

MK-Words By MMK 1999

anb this message:

Welcome To Y2K

Variants B and C also display another message box on the 3rd of the month:

Y2K is coming soon...

It also adds this message

MK-Words (V1) By MMK 1999

into the comment field of the file summary information.

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

The following should be deleted:

C:END.COM or C:END.A