WM.ShowOff

SUMMARY

WM.ShowOff is a simple macro virus that is based on WM.Concept. It does not have a malicious payload. This macro virus does not work in Microsoft Office 97 or later.

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: 11th and 13 of each month.
• Payload: a dialog box titled: Watch this !!! with a message: TO ONE OF US, PEACE ! HAPPY BIRTHDAY!!!

Distribution

• Distribution Level: Low
• Target of Infection: Microsoft Word documents.

TECHNICAL DETAILS

WM.ShowOff has three macros in documents and the global template. In a document, the macros are named

• AUTOOPEN
• SHOW
• CFXX

In the global template (NORMAL.DOT), the macros are named

• OFXX
• AUTOEXEC
• AUTOCLOSE

This macro virus infects global template upon opening an infected document. It infects other documents when the document is being closed.
The virus author is probably still learning how to write a macro virus, as there are many commented lines of code for debugging purposes. There are many comment lines (some are in Indonesian) that show the confusion of the author in some part of the viral code.

Payload

The payload is triggered on the 11th and 13th of the month. It simply displays a dialog box titled:

Watch this !!!

with a message:

TO ONE OF US, PEACE ! HAPPY BIRTHDAY!!!

Variant Notes

Most variants of WM.ShowOff have a corrupted SHOW/AUTOEXEC macro. The corruption in AUTOEXEC macro often causes Microsoft Word to display an error message when Word is launched.

Some variants of WM.ShowOff have a snatched SHOW/AUTOEXEC macro. A snatched macro can belong to another virus or can be a clean macro.
WM.ShowOff.A is the first variant that was in the wild. However, it has a corrupted SHOW/AUTOEXEC macro. WM.ShowOff.C seems to have been the original variant without any macro corruption.

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

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.