W32.Kwbot.R.Worm

SUMMARY

W32.Kwbot.R.Worm is a worm that attempts to spread through the KaZaA file-sharing network and network shares with weak passwords. It also has backdoor Trojan capabilities, which allows an attacker to gain control of a compromised computer.

W32.Kwbot.R.Worm is a variant of W32.Kwbot.Worm and is packed with Petite.

Protection

• Virus Definitions (LiveUpdate™ Weekly) October 29, 2003
• Virus Definitions (Intelligent Updater) October 24, 2003

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
• Modifies Files: Modifies system registry.
• Releases Confidential Info: Intercept confidential information by hooking any keystrokes.
• Compromises Security Settings: Allows unauthorized remote access to an infected computer.

Distribution

• Distribution Level: Medium
• Shared Drives: Copies itself to the shared folder of KaZaA.

TECHNICAL DETAILS

When W32.Kwbot.R.Worm runs, it performs the following actions:

1. Copies itself as AMSNDMGR.EXE into %System% folder.
   
   

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   Note: %System% is a variable. The worm locates the System folder and copies itself to that location. By default, this is C:WindowsSystem (Windows 95/98/Me), C:WinntSystem32 (Windows NT/2000), or C:WindowsSystem32 (Windows XP).

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2. Adds the value:
   
   "lnternet Explorer"="AMSNDMGR.EXE"
   
   to the registry keys:
   
   • HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   • HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersion
     Runonce
     
     so that the worm starts when you start or restart Windows.
     
     

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     Note: The created value that lnternet Explorer starts with is the letter L.

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3. Creates the directory %System% everagain and drops itself into it under 140 different file names. Some of which include:
   
   • DeadAIM Key Generator.exe
   • Ad-aware Proffessional 6.01 with crack.exe
   • AcdSee 5.0.1 With Crack.exe
   • Norton anti virus 2004 (BETA) crack.exe
   • L0pht Crack 4 with serial.exe
   • Tony Hawk Pro Skater 4 crack.exe
   • Trojan Remover 6.0.3 With Crack.exe
   • 3d Mark with crack.exe
   • Windows 2003 Server Keygen.exe
     
     
4. Adds the value:
   
   "Dir0"="012345:%system% everagain"
   
   to the registry key:
   
   HKEY_CURRENT_USERSoftwareKAZAALocalContent
   
   to make itself available for other KaZaa users.
   
   
5. Intercepts keystrokes and logs them in the file %System%keylog.txt.
   
   
6. Attempts to terminate the following processes:
   
   • NETSTAT.EXE
   • TASKMGR.EXE
   • MSCONFIG.EXE
   • REGEDIT.EXE
     
     
7. Attempts to replicate across the network in the following way:
   
   1. Calculates a random IP address.
   2. Attempts to authenticate to the IP addresses as Administrator using a list of predetermined passwords.
   3. Attempts to copy itself as the following:
      
      \<authenticated IP>Admin$system32pqonwe.exe
      
      
   4. Remotely schedules a task to run the worm on the newly infected computer.
      
      

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      Note: W32.Kwbot.R.Worm may also drop the legitimate application PSEXEC.EXE (Sysinternals remote execution tool), and use it to remotely execute the replicated copy.

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8. Awaits the commands from the remote client. The commands allow the hacker to perform any of the following actions:
   
   • Deliver system and network information to the hacker, including the login names and cached network passwords.
   • Intercept information currently displayed on a screen and deliver it to the hacker.
   • Download and execute files.
   • Alter many system parameters like screen resolution, system colors.
   • Perform Denial of Service (DoS) attacks.

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.Kwbot.R.Worm.
4. Delete the value that was added 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"
  

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Note: When you are completely finished with the removal procedure and are satisfied that the threat has been removed, re-enable System Restore by following the instructions in the aforementioned documents.

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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.Kwbot.R.Worm, click Delete.

4. Deleting the value from 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 and then click OK. The Registry Editor opens.
   
   
3. Navigate to the following key:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
   
4. In the right pane, delete the following value:
   
   "lnternet Explorer"="AMSNDMGR.EXE"
   
   
5. Navigate to the following key:
   
   HKEY_CURRENT_USERSoftwareKAZAALocalContent
   
   
6. In the right pane, delete the following value:
   
   "Dir0"="012345:%system% everagain"
   
   
7. Navigate to the following key:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersion
   Runonce
   
   
8. In the right pane, delete the following value:
   
   "lnternet Explorer"="AMSNDMGR.EXE"
   
   
9. Exit the Registry Editor.