W32.Bambo

SUMMARY

W32.Bambo is a Trojan Horse that attempts to steal WebMoney Keeper files, capture clipboard data, and log key strokes.

Protection

• Virus Definitions (LiveUpdate™ Weekly) July 2, 2003
• Virus Definitions (Intelligent Updater) July 2, 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: Low

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

When W32.Bambo is executed, it does the following:

1. Copies itself as the following files:
   • %Windir%Dllreg.exe
   • %System%Load32.exe
   • %System%Vxdmgr32.exe
   • %StartUp%undllw.exe
     
     
2. Adds the value:
   
   "load32"="%System%load32.exe"
   
   to the registry key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
   
   so that the Trojan runs when you start Windows.
   
   
3. Adds the line:
   
   run=C:WindowsDllreg.exe
   
   to the Win.ini file so that the Trojan runs when you start Windows 95/98/Me.
   
   
4. Modifies the shell= line in the System.ini file to:
   
   shell=explorer.exe C:WINDOWSSYSTEMvxdmgr32.exe
   
   so that the Trojan runs when you start Windows 95/98/Me.
   
   
5. Drops the file, %Windows%Sysdrv.exe, and then executes it. This file will terminate the following processes:
   _avp32.exe
   _avpcc.exe
   _avpm.exe
   Agentsvr.exe
   Anti-trojan.exe
   Ants.exe
   Aplica32.exe
   Apvxdwin.exe
   Atcon.exe
   Atupdater.exe
   Atwatch.exe
   Autoupdate.exe
   Avconsol.exe
   Avp.exe
   Avp32.exe
   Avpcc.exe
   Avpcc.exe
   Avpm.exe
   Avsynmgr.exe
   Blackd.exe
   Blackice.exe
   Cfiadmin.exe
   Cfiaudit.exe
   Cfinet.exe
   Cfinet32.exe
   Cleaner.exe
   Cleaner3.exe
   Defwatch.exe
   Drwatson.exe
   Fast.exe
   Frw.exe
   Fsav.exe
   Guard.exe
   Iamapp.exe
   Iamserv.exe
   Icload95.exe
   Icloadnt.exe
   Icmon.exe
   Icsupp95.exe
   Icsuppnt.exe
   Lockdown.exe
   Lockdown2000.exe
   Luall.exe
   Lucomserver.exe
   Mcagent.exe
   Mcupdate.exe
   Mgui.exe
   Minilog.exe
   Moolive.exe
   Msconfig.exe
   Mssmmc32.exe
   Navapw32.exe
   Navw32.exe
   Navw32.exe
   Ndd32.exe
   Netstat.exe
   Nisserv.exe
   Nisum.exe
   Nmain.exe
   Nprotect.exe
   Nsched32.exe
   Nvarch16.exe
   Pavproxy.exe
   Pcciomon.exe
   Pcfwallicon.exe
   Persfw.exe
   Poproxy.exe
   Pview95.exe
   Regedit.exe
   Rtvscn95.exe
   Safeweb.exe
   Sphinx.exe
   Spyxx.exe
   Ss3edit.exe
   Sysedit.exe
   Taumon.exe
   Tc.exe
   Tca.exe
   Tcm.exe
   Tds2-98.exe
   Tds2-nt.exe
   Tds-3.exe
   Trjscan.exe
   Update.exe
   Update.exe
   Vpc42.exe
   Vptray.exe
   Vsecomr.exe
   Vshwin32.exe
   Vsmain.exe
   Vsmon.exe
   Vsstat.exe
   Watchdog.exe
   Webscanx.exe
   Wgfe95.exe
   Wradmin.exe
   Wrctrl.exe
   Wrctrl.exe
   Zapro.exe
   Zatutor.exe
   Zauinst.exe
   Zonealarm.exe
   
   NOTE: Symantec AntiVirus products detect the Sysdrv.exe file as a Trojan Horse.
   
   
6. If the operating system is Windows 95/98/Me, it adds the value:
   
   "ZoneAlarm 2.99"="%Windows%Sysdrv.exe"
   
   to the registry key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersion
   RunServices
   
   
7. Begins logging key strokes, capturing clipboard data, and finding the .kwm and .pwm files. The WebMoney Keeper program uses these two files. Then, the Trojan sends the captured information to a specific email address.

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.

NOTE: These instructions assume that the computer is already infected with W32.Bambo and that the Trojan has executed and is running. If your Symantec antivirus product detects W32.Bambo when the Trojan attempts to execute, this indicates that W32.Bambo has been caught and prevented from running. In this situation, delete W32.Bambo, and to be secure, follow the instructions in Sections 5 and 6 below:

1. Restart the computer in Safe mode or VGA mode.
2. Delete the values that were added to the registry.
3. Delete the lines that were added to the Win.ini and System.ini files (Windows 95/98/Me).
4. Disable System Restore (Windows Me/XP).
5. Update the virus definitions.
6. Run a full system scan and delete all the files detected as W32.Bambo.

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

1. Restarting 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, refer to the document, "How to start the computer in Safe Mode."
• For Windows NT 4 users, restart the computer in VGA mode.

2. Deleting the value from the registry

CAUTION: 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.

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_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
   
4. In the right pane, delete the value:
   
   "load32"="%System%load32.exe"
   
   
5. If you are running Windows 95/98/Me, navigate to the key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersion
   RunServices
   
   
6. In the right pane, delete the value:
   
   "ZoneAlarm 2.99"="%Windows%Sysdrv.exe"
   
   
7. Exit the Registry Editor.
8. Follow the instructions for your operating system:
   • Windows 95/98/Me: Proceed to Section 3.
   • Windows NT/2000/XP:
     1. Shut down the computer, turn off the power, and wait 30 seconds.
     2. Restart the computer in Normal mode. When the computer restarts, proceed to section 5.

3. Deleting the lines that were added to the Win.ini and System.ini files
If you are running Windows 95/98/Me, follow these steps:

1. The function you perform depends on your operating system:
   • Windows 95/98: Proceed to step b.
   • Windows Me: If you are running Windows Me, the Windows Me file-protection process may have made backup copies of the Win.ini and System.ini files that you need to edit. If these copies exist, it will be in the C:WindowsRecent folder. Symantec recommends that you delete these files before continuing with the steps in this section. To do this:
     1. Start Windows Explorer.
     2. Browse to and select the C:WindowsRecent folder.
     3. In the right pane, select the Win.ini file and the System.ini files, and then delete them. The files will be regenerated when you save your changes to them in the following step.
        
        
2. Click Start, and then click Run.
3. Type the following, and then click OK.
   
   edit c:windowswin.ini
   
   (The MS-DOS Editor opens.)
   
   NOTE: If Windows is installed in a different location, make the appropriate path substitution.
   
   
4. Look for a line similar to:
   
   run=C:WindowsDllreg.exe
   
   
5. If this line exists, delete it.
6. Click File, and then click Save.
7. Click File, and then click Exit.
8. Click Start, and then click Run.
9. Type the following, and then click OK.
   
   edit c:windowssystem.ini
   
   
10. Look for the line:
    
    shell=explorer.exe C:WINDOWSSYSTEMvxdmgr32.exe
    
    
11. If this line exists, delete everything to the right of Explorer.exe.
    
    When you are done, it should look like:
    
    shell=explorer.exe
    
    
12. Click File, and then click Save.
13. Click File, and then click Exit.
14. Shut down the computer, turn off the power, and wait 30 seconds.
15. Restart the computer in Normal mode. When the computer restarts, proceed to Section 4.

4. 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.

5. 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.

6. 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.Bambo, click Delete.