W32.Celebite.Worm

SUMMARY

W32.Celebite.Worm is a peer-to-peer worm written in Visual Basic. It spreads using KaZaA.

Note: Virus definitions were updated on September 29, 2003 to account for the discovery of a minor variation.

Protection

• Virus Definitions (LiveUpdate™ Weekly) June 3, 2003
• Virus Definitions (Intelligent Updater) June 3, 2003

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.Celebite.Worm runs, it performs the following actions:

1. Creates the folder %Windir%Celebite.
   
   

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   Note: %Windir% is a variable. The Trojan locates the Windows installation folder (by default, this is C:Windows or C:Winnt) and creates the folder in that location.

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2. Copies itself as any number of files in the %Windir%Celebite folder. These file names are randomly generated from a list of verbs, adjectives, and proper names. The file names start with one of the following adjectives:
   
   Nude
   Naked
   Horney
   
   and then adds one of the following names (the spelling is as it appears in the worm text):
   
   Birtney Spears
   Christina Angulera
   Madonna
   Alica Keys
   Alica Silverstone
   Demi Moore
   Carmen Electra
   Liv Taylor
   Anna Kournikova
   Justin Kimberlake
   Eminem
   Dr Dre
   Bill Clinton
   Spiderman
   Someone
   Brad Pittt
   Tom Cruise
   Alan Donnald
   Superman
   
   The file name continues with a verb, usually describing a sexual act, and then one of the names again. Last, the worm might add one of the following to complete the filename:
   
   Wallpaper Collection
   Screensaver
   Picture Collection
   3d ScreenSaver
   
   Then, the filename ends with a .exe extension. The internal name of the files (in the Properties sheet) is always "Attach.exe."
   
   
3. Changes the KaZaA settings in the registry to point to the %Windir%Celebite area as the shared folder. The registry settings are set to:
   
   HKEY_CURRENT_USERSoftwareKazaaAdvancedScanfolder = "0"
   
   HKEY_CURRENT_USERSoftwareKazaaLocalContentdir0 = "012345:%Windir%Celebite"
   
   HKEY_CURRENT_USERSoftwareKazaa\LocalContentdisablesharing = "0"
   
   
   The previous two keys force the sharing of the Celebite folder and its contents.
   
   
   HKEY_CURRENT_USERSoftwareKazaaResultsFilteradult_filter_level = "0"
   
   HKEY_CURRENT_USERSoftwareKazaaResultsFilterogus_filter = "0"
   
   HKEY_CURRENT_USERSoftwareKazaaResultsFilterFirewall_filter = "0"
   
   HKEY_CURRENT_USERSoftwareKazaaResultsFilterVirus_filter = "0"
   
   
   The previous four keys disable KaZaA filtering.
   
   
   HKEY_CURRENT_USERSoftwareKazaaResultsFiltercustom_filter_phrases = ""
   
   HKEY_CURRENT_USERSoftwareKazaaUserDetailsautoconnect = "0"
   
   HKEY_CURRENT_USERSoftwareKazaaUserDetails ewsletter = "0"
   
   HKEY_CURRENT_USERSoftwareKazaaUserDetailsusername = "Celebite"
   

The worm includes the text:

My name is Celebite, and on this PC my babies fly!

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

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

1. Disable System Restore (Windows Me/XP).
2. Update the virus definitions.
3. Run a full system scan and delete all the files detected as W32.Celebite.Worm.
4. If you use KaZaA, reverse the changes that were made to the registry.
   

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

1. Disabling System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:

• "How to disable or enable Windows Me System Restore"
• "How to turn off or turn on Windows XP System Restore"

For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article, "Antivirus Tools Cannot Clean Infected Files in the _Restore Folder," Article ID: Q263455.

2. 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 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).
• 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).
  
  The Intelligent Updater virus definitions are available: Read "How to update virus definition files using the Intelligent Updater" for detailed instructions.

3. 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 W32.Celebite.Worm, click Delete.

4. Reversing the changes that were made to the registry

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

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1. Click Start, and then click Run. (The Run dialog box appears.)
2. Type regedit
   
   Then click OK. (The Registry Editor opens.)
   
   
3. Navigate to the key:
   
   HKEY_CURRENT_USERSOFTWAREKazaaAdvanced
   
   In the right pane, delete or reset the value:
   
   "scanfilter"="0"
   
   
4. Navigate to the key:
   
   HKEY_CURRENT_USERSOFTWAREKazaaLocalContent
   
   
5. In the right pane, delete or reset the values:
   
   "dir0" = "012345:%windir%Celebite" (should be reset to the default KaZaA shared directory
   "disablesharing" = "0"
   
   
6. Navigate to the key:
   
   HKEY_CURRENT_USERSOFTWAREKazaaResultsFilter
   
   
7. In the right pane, delete or reset the values:
   
   "adult_filter_level" = "0"
   "bogus_filter" = "0"
   "Firewall_filter" = "0"
   "Virus_filter" = "0"
   "custom_filter_phrases" = ""
   
   
8. Navigate to the key:
   
   HKEY_CURRENT_USERSOFTWAREKazaaUserDetails
   
   
9. In the right pane, delete or reset the values:
   
   "autoconnect" = "0"
   "newsletter" = "0"
   "Username" = "Celebite"
   
   
10. Exit the Registry Editor.