W32.Spybot.ABDO

1. Checks for the presence of a debugger and ends itself if one is found on the compromised computer. The worm performs the same action if it detects that it is running on a VMware virtual machine.
   
   
2. Copies itself as the following file:
   
   %Windir%\lsass.exe
   
   Note: %Windir% is a variable that refers to the Windows installation folder. By default, this is C:\Windows or C:\Winnt.
   
   
3. Registers itself as a service with the following characteristics:
   
   Service Name: lsass
   Display Name: Local Security Authority Subsystem Service
   Description: Microsoft Path Finder Service Displays Internet Routing Paths
   
   This service is configured so that is starts automatically during the boot sequence, and also restarts after 3 seconds if it is ended.
   
   
4. Modifies the value:
   
   "EnableDCOM" = "N"
   
   in the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\OLE
   
   in order to disable DCOM.
   
   
5. May modify the value:
   
   "restrictanonymous" = "1"
   
   in the registry subkey:
   
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
   
   in order to restrict null sessions.
   
   
6. Modifies the value:
   
   "DoNotAllowXPSP2" = "1"
   
   in the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Windows\WindowsUpdate
   
   to prevent the installation of Windows XP Service Pack 2 on the compromised computer.
   
   
7. Modifies the value:
   
   "EnableFirewall" = "0"
   
   in the registry subkeys:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Windows\WindowsFirewall\StandardProfile
   HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Windows\WindowsFirewall\DomainProfile
   
   to disable the Windows firewall.
   
   
8. Modifies the value:
   
   "UpdatesDisableNotify" = "1"
   
   in the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
   
   to disable notification of update status through the Windows Security Center.
   
   
9. Modifies the values:
   
   "AntiVirusOverride" =  "1"
   "FirewallOverride" = "1"
   
   in the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
   
   to stop monitoring firewall and antivirus status.
   
   
10. Modifies the value:
    
    "AUOptions" = "1"
    
    in the registry subkey:
    
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\AUOptions
    
    to disable Automatic Update.
    
    
11. Attempts to stop the following Windows services:
    
    
    • Tlntsvr (Telnet)
    • RemoteRegistry (Remote Registry)
    • Messenger (Messenger)
    • SharedAccess (Windows Firewall/ICS)
    • wscsvc (Security Center)
      
      
12. Opens a back door by connecting to an IRC server on the following domain through TCP port 53:
    
    sm2.phase7.org
    
    
13. Allows a remote attacker to use IRC commands to perform the following actions:
    
    
    • Download and execute files
    • List, stop, and start processes and threads
    • Launch ACK, SYN, UDP, and ICMP Denial of Service (DoS) attacks
    • Perform port redirection
    • Send files over IRC
    • Send email using its own SMTP engine
    • Start a local HTTP, FTP, or TFTP server
    • Search for files on the compromised computer
    • Log keystrokes to file Access network shares and copy itself to those network shares
    • Scan the network for vulnerable hosts by means of port scanning
    • Captures screenshots, data from the clipboard, and video from webcams
    • Visit URLs Intercept packets on the local area network
    • Flush the DNS and ARP caches
    • Open a command shell on the infected computer
    • Start a SOCKSv4 proxy server
    • Add and delete network shares and disable DCOM
    • Reboot the infected computer
    • Send messages in AOL Instant Messenger to all the victim's contacts
      
      
14. Sends the following message using the AOL Instant Messenger sending feature:
    
    This AIM user has sent you a Christmas Card! To open it please visit:
    [http:/ /]greetings.aol.com/[REMOVED]/index.pd?source=greetingscard?my_christmas_card.scr
    
    Note: The real link differs from the displayed link and points to a copy of the worm.
    
    
15. Spreads to other computers by exploiting the following vulnerabilities:
    
    
    • The Microsoft Windows DCOM RPC Interface Buffer Overrun Vulnerability (as described in Microsoft Security Bulletin MS03-026)
    • The Microsoft Windows Local Security Authority Service Remote Buffer Overflow Vulnerability (as described in Microsoft Security Bulletin MS04-011)
      
      
16. Attempts to spread to randomly generated IP addresses by copying itself to network shares protected by weak passwords.

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.