Lifeform.2054

SUMMARY

Lifeform.2054 is a memory-resident DOS virus that infects .com files.

The virus is encrypted using a simple polymorphic one-byte xor encryption. This means that the key will change between infections. The decryption routine for this virus contains several simple antidebugging tricks.

NOTE: Definitions that have dates earlier than February 11, 2003, detect this virus as BloodHound.ResCOM.

Protection

• Virus Definitions (LiveUpdate™ Weekly) February 12, 2003
• Virus Definitions (Intelligent Updater) February 11, 2003

REMOVAL

The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Update the virus definitions.
2. Run a full system scan, and delete all files that are detected as Lifeform.2054. Replace the files, if necessary.

For specific details on each of these procedures, read the following instructions.

1. Updating the virus definitions

Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:
• Running LiveUpdate, which is the easiest way to obtain the virus definitions: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to the Virus Definitions (LiveUpdate), in the "Protection" section, at the top of this write-up.
• Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to the Virus Definitions (Intelligent Updater), in the "Protection" section, at the top of this write-up.
  
  The 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. Scanning for and deleting the infected files

1. Start your Symantec antivirus program, and make sure that it is configured to scan all the files.
   • For Norton AntiVirus consumer products: Read the document "How to configure Norton AntiVirus to scan all files."
   • For Symantec AntiVirus Enterprise products: Read the document "How to verify that a Symantec Corporate antivirus product is set to scan All Files."
2. Run a full system scan.
3. If any files are detected as infected with Lifeform.2054, click Delete.
4. If necessary, replace deleted files from a clean backup or reinstall them.