W32.Kibuv.E

SUMMARY

W32.Kibuv.E is a minor variant of W32.Kibuv.C. It is a worm that attempts to spread itself through IRC, FTP, and by exploiting vulnerabilities.

Protection

• Virus Definitions (LiveUpdate™ Weekly) May 26, 2004
• Virus Definitions (Intelligent Updater) May 25, 2004

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Moderate

Damage

• Damage Level: Medium
• Compromises Security Settings: Opens backdoor on port 420/TCP; starts FTP server on port 7955/TCP

Distribution

• Distribution Level: Medium
• Ports: TCP ports 420, 7955, 44444, 44445, 44446

TECHNICAL DETAILS

When W32.Kibuv.E is executed, it performs the following actions:

1. Starts an FTP server that accepts any username and password combination on TCP port 7955. All connections attempting to download files from the FTP server will receive a copy of the worm.
   
   
2. Connects to one of the following IRC servers and waits for commands from an attacker:
   • w3rd3.no-ip.com (Uses ports 44444, 44445, 44446)
   • w3rd2.no-ip.com (Uses port 44444, 44445)
   • w3rd1.no-ip.com (Uses ports 44444, 44445)
     
     
3. May attempt to scan for and exploit one of the following vulnerabilities in order to spread:
   • Buffer Overrun in Messenger Service (described in Microsoft Security Bulletin MS03-043).
   • IIS 5.0 WebDAV3 (described in Microsoft Security Bulletin MS03-007).
   • The UPnP NOTIFY Buffer Overflow Vulnerability (described in Microsoft Security Bulletin MS01-059).
     This vulnerability is exploited by sending a specially crafted NOTIFY directive to the UPnP service, which listens on TCP port 5000.
   • Buffer Overrun In RPC Interface (described in Microsoft Security Bulletin MS03-026).
   • LSASS vulnerability (described in Microsoft Security Bulletin MS04-011).
   • The backdoors created by W32.Weird and W32.Beagle@mm. (The port numbers are configurable.)
   • The FTP server the W32.Sasser family of worms creates.
     

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     Note: An attacker must instruct the worm to use any of the above vulnerabilities.

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4. Attempts to connect to other IRC servers and send an address to IRC users.
   
   For example, it may send "ftp://z:z@<the.ipaddress.of.infected.computer>:7995/bot.exe".
   
   
5. Listens on TCP port 420 and waits for commands from the remote attacker.
   
6. Adds the value:
   
   "Ms Autoupdate"="path to original file name"
   
   to the registry keys:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersion
   RunServices
   
   
   so that the worm runs when you start Windows.

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 XP).
2. Update the virus definitions.
3. Restart the computer in Safe mode or VGA mode.
4. Run a full system scan and delete all the files detected as W32.Kibuv.E.
5. Reverse the changes that the worm made to the registry.
   

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

1. To disable System Restore (Windows 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. To update 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. To restart the computer in Safe mode or VGA mode
Shut down the computer and turn off the power. Wait for at least 30 seconds, and then restart the computer in Safe mode or VGA mode.

• For Windows 95, 98, Me, 2000, or XP users, restart the computer in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode."
• For Windows NT 4 users, restart the computer in VGA mode.
  

4. To scan for and delete 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.Kibuv.E, click Delete.

5. To reverse the changes 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 > Run. (The Run dialog box appears.)
2. Type regedit
   
   then click OK. (The Registry Editor opens.)
   
   
3. Navigate to the key
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
   
4. In the right pane, delete the value:
   
   "MS Autoupdate" = "<Trojan path and file name>"
   
   
5. Navigate to the key
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersion
   RunServices
   
6. In the right pane, delete the value:
   
   "MS Autoupdate" = "<Trojan path and file name>"
   
7. Exit the Registry Editor.