W32.Opanki.P

1. Copies itself as the following file:
   
   %Windir%\antivirus32.exe
   
   Note: %Windir% is a variable that refers to the Windows installation folder. By default, this is C:\Windows or C:\Winnt.
   
   
2. Creates the following registry subkeys:
   
   HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\antivirus32
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\antivirus32
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_ANTIVIRUS32
   HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\Root\LEGACY_ANTIVIRUS32
   
   to create the service antivirus32.
   
   
3. Adds the values:
   
   "AntiVirusDisableNotify" = "1"
   "AntiVirusOverride" = "1"
   "FirewallDisableNotify" = "1"
   "FirewallOverride" = "1"
   "UpdatesDisableNotify" = "1"
   
   to the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
   
   to disable various Security Center functions.
   
   
4. Adds the value:
   
   "EnableFirewall" = "0"
   
   to the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\DomainProfile
   
   to disable the Windows Firewall.
   
   
5. Adds the value:
   
   "EnableFirewall" = "0"
   
   to the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\StandardProfile
   
   to disable the Windows Firewall.
   
   
6. Adds the value:
   
   "DoNotAllowXPSP2" = "1"
   
   to the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate
   
   to stop Windows XP Service Pack 2 from being downloaded.
   
   
7. Adds the value:
   
   "AUOptions" = "0"
   
   to the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update
   
   to lower security settings.
   
   
8. Modifies the value:
   
   "EnableDCOM" = "N"
   
   in the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Ole
   
   to disable DCOM.
   
   
9. Adds the value:
   
   "EnableFirewall" = "0"
   
   to the registry subkeys:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\DomainProfile
   HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\StandardProfile
   
   
10. Modifies the value:
    
    "restrictanonymous" = "1"
    
    in the registry subkey:
    
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
    
    to prevent NULL session enumeration of the host.
    
    
11. Modifies the value:
    
    "Start" = "4"
    
    in the registry subkeys:
    
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Messenger
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RemoteRegistry
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TlntSvr
    
    
12. Modifies the value:
    
    "WaitToKillServiceTimeout" = "7000"
    
    in the registry subkey:
    
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control
    
    
13. Adds the value:
    
    "(Default)" = "10"
    
    to the registry subkey:
    
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ServiceCurrent
    
    
14. Adds the value:
    
    "Epoch" = "10"
    
    to the registry subkey:
    
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Epoch
    
    
15. Spreads to computers by exploiting the following vulnerabilities:
    
    
    • The Microsoft Windows LSASS Buffer Overrun Vulnerability (as described in Microsoft Security Bulletin MS04-011)
    • The Microsoft Windows DCOM RPC Interface Buffer Overrun Vulnerability (as described in Microsoft Security Bulletin MS03-026)
    • The Microsoft Windows Workstation Service Remote Buffer Overflow vulnerability (as described in Microsoft Security Bullettin MS03-049)
    • The Microsoft Windows Plug and Play Buffer Overflow Vulnerability (as described in Microsoft Security Bulletin MS05-039)
    • The Microsoft ASN.1 Library Multiple Stack-Based Buffer Overflow vulnerabilities (as described in Microsoft Security Bulletin MS04-007)
      
      
16. Spreads to network shares that can be accessed from the compromised computer.
    
    
17. Connects to an IRC channel on the gvd.pepenterror.net server through TCP port 3132 and listens for commands that allow the remote attacker to perform the following actions:
    
    
    • Spread itself through AIM, Yahoo, MSN and ICQ messenger
    • Download and execute remote files
    • Denial of service attacks
    • Update itself
    • Start and stop services
    • Add and remove registry values
      

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
• 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.
• Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
• Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
• Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
• Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
• If a 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate compromised computers quickly to prevent threats from spreading further. 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.
• If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
• For further information on the terms used in this document, please refer to the Security Response glossary.