W97M.Antiv.A

SUMMARY

W97M.Antiv.A infects Microsoft Word documents and the Normal.dot template.

Protection

• Virus Definitions (Intelligent Updater) January 10, 2001

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
• Compromises Security Settings: Disables Word macro virus protection

Distribution

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

TECHNICAL DETAILS

When an infected document is opened, the virus copies its viral macro to the Nomal.dot template. Thereafter, all documents that are opened in Word using this template will be infected. This virus also disables Microsoft Word macro virus protection.

After the infection occurs, when you open a document that contains macros that are not named either of the following:

• Hunter
• ThisDocument

you see a dialog box with a message in Portuguese. The translation of the message is:

These type of macros are usually viruses. Do you want to delete it?

If you click Yes, it will delete the macros.

The virus also creates two log files:

• C:Msg
• C:Program FilesMicrosoft OfficeOfficeHunter_log.txt

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

To repair this virus:

1. Run LiveUpdate to make sure that you have the most recent virus definitions.
2. Run a full system scan, making sure that Norton AntiVirus (NAV) is set to scan all files.
3. If NAV detects files as infected with W97M.Antiv.A, choose Repair.
4. (Optional) Use Windows Explorer to locate and delete the following files:
   • C:Msg
   • C:Program FilesMicrosoft OfficeOfficeHunter_log.txt