W95.BlueCorners.2049

SUMMARY

This virus is a fairly simple fast infector. It will infect only Windows 9x computers, and it will fail if run on Windows NT computer.

This virus carries a non-destructive payload that is activated on specific dates.

Protection

• Virus Definitions (Intelligent Updater) June 21, 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
• Payload Trigger: Date is equal to one of: 1st of January, 14th of February, 1st of April, 4th of May, 1st of October or 25th of December.
• Payload: Intrusive Graphical animations on the screen

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

When executed, this virus performs the following actions:

1. It starts by running the host program in a separate process.
2. Next, it infects all .exe files on the same drive as the virus, and on the C drive (if the virus is located elsewhere.)
   
   NOTES:
   • This virus does not become memory-resident, but it does use a memory location allocated to the operating system to indicate whether to infect the system or not. This simply means that the virus will only try to infect files once, after the system has been rebooted.
   • Some systems may crash randomly, since this memory location is intended for use by the system. This virus also uses this memory location in such a fashion that if more than 4 logical drives are hooked to the system, then it will try to infect files every time that it is activated.
3. When it is finished infecting files, this virus checks if the date is one of the following:
   • January 1
   • February 14
   • April 1
   • May 4
   • October 1
   • December 25

If it is, it activates its payload routine, which animates a number of small blue balls in the four corners of the screen (one corner is shown in the following picture).



The payload assumes that the screen resolution is 800x600 so that , depending on the resolution, the upper right corner, lower right corner and lower left corner balls may appear elsewhere.

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 run a full system scan, making sure that NAV is set to scan all files.
3. If any files are detected as infected by this virus, choose Repair.