W32.Beast.41472

SUMMARY

W32.Beast.41472 is a stand-alone executable that infects Microsoft Word documents by embedding itself in them. It adds an AutoOpen macro to the document
to run the embedded virus when the document is opened.

Norton AntiVirus detects both the stand-alone virus and the documents that contain the virus in them.

Protection

• Virus Definitions (LiveUpdate™ Weekly) March 1, 1999
• Virus Definitions (Intelligent Updater) March 1, 1999

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

When the virus is executed it does the following:

It copies itself to the WindowsSystem folder as a random file name with the .exe extension. Usually the random file names are seven or eight characters in length.

The virus then adds the value

<random name> <random name.exe>

to the registry key

HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun

so that it runs when you start Windows.

The virus then stays in memory and begins to infect Microsoft Word documents by embedding itself in them. It does this by first creating a copy of itself as C:i.exe; it then uses that file to embed in the infected document. After embedding itself, the virus adds a AutoOpen macro to the infected document to activate the embedded virus.

Once the virus is embedded in the infected document, the virus deletes the i.exe file.

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 remove this virus, delete .exe files detected as W32.Beast.41472, repair Word files that are detected as W32.Beast.41472, and remove the value that the virus added to the registry.

To remove and repair infected files:

1. Obtain the most recent virus definitions. There are two ways to do this:
   • Run LiveUpdate. LiveUpdate is the easiest way to obtain virus definitions. These virus definitions have undergone full quality assurance testing by Symantec Security Response and are posted to the LiveUpdate servers one time each week (usually Wednesdays) unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, look at the Virus Definitions (LiveUpdate) line at the top of this write-up.
   • Download the definitions using the Intelligent Updater. Intelligent Updater virus definitions have undergone full quality assurance testing by Symantec Security Response. They are posted on U.S. business days (Monday through Friday). They must be downloaded from the Symantec Security Response Web site and installed manually. To determine whether definitions for this threat are available by the Intelligent Updater, look at the Virus Definitions (Intelligent Updater) line at the top of this write-up.
     
     Intelligent Updater virus definitions are available here. For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, click here.
     
2. Start Norton AntiVirus (NAV), and make sure that NAV is configured to scan all files. For instructions on how to do this, read the document How to configure Norton AntiVirus to scan all files.
3. Run a full system scan.
4. Delete all .exe files that are detected as infected by W32.Beast.41472.
5. Repair all Microsoft Word documents that are detected as infected by W32.Beast.41472.

To remove the value from the registry:

CAUTION: Symantec strongly recommends that you back up the registry before you make any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify only the keys that are specified. Read the document How to make a backup of the Windows registry for instructions.

1. Click Start, and click Run. The Run dialog box appears.
2. Type regedit and then click OK. The Registry Editor opens.
3. Navigate to the following key:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
4. In the right pane, delete the following value:
   
   <random name> <random name.exe>
   
5. Click Registry, and click Exit.