WM.Niknat

SUMMARY

WM.Niknat replicates upon closing a document. During its infection routine, it attempts to create a picture file named EVAH.BMP in a hidden directory: C:EVAHZG2.

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: October 23
• Payload: Displays " Windows Protection Error"
• Modifies Files: Change desktop color pallette and wallpaper to EVAH.BMP, created by the virus.

Distribution

• Distribution Level: Low
• Target of Infection: MS Word documents, Windows desktop.

TECHNICAL DETAILS

In infected Global Template, this macro virus has 5 macros:

• EVAHZG
• DCLOSEAN
• AUTOCLOSE
• TOOLSMACRO
• FILETEMPLATES

In infected documents, it has these 5 macros:

• EVAHZG
• TCLOSEAN
• AUTOCLOSE
• TOOLSMACRO
• FILETEMPLATES

File/Templates and Tools/Macro command are disabled and are modified to display the following message:

Windows Protection Error

Payload

On October 23, it will change the color palette and replace Windows 95 wallpaper with the inserted C:EVAHZG2EVAH.BMP picture.

Variant Notes

Most variants of WM.Niknat have a corrupted EVAHZG macro.

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

Although the following created directories and inserted files are harmless, you may want to remove them:

• C:EVAHZG2
• C:WINDOWSCOMMANDEVAH.NIK
• C:WINDOWSCOMMANDEVAHZ.BAT
• C:WINDOWSCOMMANDEVAH.BMP

Norton AntiVirus users can protect themselves from this virus by downloading the current virus definitions either through LiveUpdate or from the Download Virus Definition Updates page.