W32.Orpheus.A

SUMMARY

W32.Orpheus.A is a network-aware worm that opens a backdoor on the infected host.

Note: Virus definitions dated prior to November 10, 2004 may detect this threat as W32.Cerberus.A.

Protection

• Virus Definitions (LiveUpdate™ Weekly) November 9, 2004
• Virus Definitions (Intelligent Updater) November 9, 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
• Payload: Allows unauthorized remote access.
• Releases Confidential Info: May be used to log keystrokes.
• Degrades Performance: May be used to perform a DoS attack.

Distribution

• Distribution Level: Medium
• Shared Drives: Attempts to copy to all domains viewable from the infected machine.

TECHNICAL DETAILS

When W32.Orpheus.A is executed, it performs the following actions:

1. Checks the following registry value:
   
   HKEY_LOCAL_MACHINESoftwareCerberus1.1dontInstall
   
   If the value is set, the worm will exit without performing any further actions.
   
   
2. Copies itself to %System%hotplug.exe.
   
   Note: %System% is a variable that refers to the System folder. By default, this is C:WindowsSystem (Windows 95/98/Me), C:WinntSystem32 (Windows NT/2000), or C:WindowsSystem32 (Windows XP).
   
   
3. Creates the service:
   
   "Hotplug Devices Manager"
   
   associating it with:
   
   %System%hotplug.exe
   
   so that it is executed on boot time with SYSTEM privileges.
   
   Note: This service will have the following description: Enables automated driver loading for hotpluggable devices, including USB, FireWire and Hotplug PCI systems. If this service is stopped, hotplug devices will no longer function. If this service is disabled, any services that explicitly depend on it will fail to start.
   
   
4. Adds the value:
   
   "DependOnService" = "HotPlug"
   
   to the registry key:
   
   HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesPlugPlay
   
   so that the Microsoft Plug n Play service depends on the worms newly installed malicious service for startup.
   
   
5. Injects ntadint.dll in any running process with a name containing the string "lsass." This dll contains the backdoor and network-spreading features of the worm.
   
   
6. When the dll is executed, it patches the following APIs to try to hide its presence on the system.
   
   • CreateProcessA
   • CreateProcessW
   • LoadLibraryExW
   • FreeLibrary
   • CreateProcessAsUserA
   • CreateProcessAsUserW
   • FindFirstFileExW
   • FindNextFileW
   • RegCloseKey
   • RegEnumKeyW
   • RegEnumKeyA
   • RegEnumKeyExW
   • RegEnumKeyExA
   • RegEnumValueW
   • RegEnumValueA
   • RegQueryMultipleValuesA
   • RegQueryMultipleValuesW
   • EnumServicesStatusA
   • EnumServicesStatusW
   • DispatchMessageA
   • DispatchMessageW
   • GetMessageA
   • GetMessageW
   • LogonUserW
   • LogonUserA
   • RegOpenKeyExW
   • RegQueryValueExW
   • WlxLoggedOutSAS
     
     The dll will attempt to inject itself into any process making a call to these APIs.
     
     
7. May log user keystrokes to c:irdos.sys.
   
   
8. Opens a backdoor on the system by creating the following named pipe:
   
   cb_win_nt_proc_rpc_[current process id]
   
   
9. Once connected, the remote user can perform a number of actions including:
   
   
   • View system details.
   • Retrieve keystroke log files.
   • Clear keystroke log files.
   • Change user passwords.
   • Create a user.
   • Delete users.
   • Execute a command.
   • Perform a DoS on a specified remote host.
   • Open shares.
     
     
10. Uses the output of the command:
    
    net view /domain
    
    to iterate through all the domains known to the infected host, attempting to connect to all the listed hosts.
    
    
11. If a successful connection is made, it will attempts to copy the following files:
    
    • %System% tadint.dll
    • %System%hotplug.exe
    • d:hotplug.exe
    • d: tadint.dll
      
      to the remote host.
      
      
12. Creates the following services on the remote computer:
    
    • Hotplug Devices Manager
    • Microsoft Windows Hotplug Service
      
      so that each of these files will be executed on system startup.

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.Orpheus.A
4. Delete the value that was added to the registry.
   

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

1. To disable 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"

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.


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 daily. 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 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.Orpheus.A, click Delete.
   
   
   Note: If your Symantec antivirus product reports that it cannot delete an infected file, Windows may be using the file. To fix this, run the scan in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode." Once you have restarted in Safe mode, run the scan again.
   
   (After the files are deleted, you can leave the computer in Safe mode and proceed with section 4. When that is done, restart the computer in Normal mode.)
   

4. To delete the value from the registry


Important: 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 > Run.
2. Type regedit
   
   Then click OK.
   
   
3. Navigate to the key:
   
   HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesPlugPlay
   
   
4. In the right pane, delete the value:
   
   "DependOnService" = "HotPlug"
   
   
5. Exit the Registry Editor.