W32.Kan

SUMMARY

W32.Kan is a very simple virus. The viral body is only 132 bytes in size. When executed, the virus attempts to infect all executable files in the Windows folder.

NOTE: This virus requires the file Invictus.dll to execute. Norton has detected Invictus.dll as W32.Invictus.dll since August 22, 2001.

Protection

• Virus Definitions (Intelligent Updater) September 18, 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

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

When W32.Kan is executed, it obtains the path to the Windows folder, and then sets the Windows folder as the current folder. Next, the virus goes into a simple FindFirst/FindNext loop, looking for executable files. It attempts to infect all executable files that it finds. The only way that the virus can exit the loop is when an error occurs or when it is unable to find any additional executable files.

The viral body of this virus is only 132 bytes in size. The reason is that this virus uses the Invictus.dll files in its infection routine. The virus simply passes the name of the file that should be infected to a function in Invictus.dll named "_infect_file." It is this function that actually infects the file.

NOTE: Based on the samples that have been received, it appears that in most cases this virus corrupts the file instead of infecting it.

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

1. Run LiveUpdate to make sure that you have the most recent virus definitions.
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 files that are detected as W32.Kan. You will need to replace deleted files from a clean backup or reinstall them.