BAT.Igador

SUMMARY

BAT.Igador is a batch script worm that spreads using Internet Relay Chat (IRC).

Protection

• Virus Definitions (LiveUpdate™ Weekly) October 12, 2004
• Virus Definitions (Intelligent Updater) October 11, 2004

TECHNICAL DETAILS

When BAT.Igador runs, it performs the following actions:

1. Copies itself to the following files:
   • %Windir%svr32.bat
   • %Windir%winlogon32.bat
   • %Windir%logfile.bat
   • %Windir% main97.bat
   • %Windir%system32 tscript.bat
   • %Windir%system32horse.exe
   • %Windir%system32mirc.bat
     
     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 directories:
   • %ProgramFiles%mIRCv16
   • %ProgramFiles%WinZip10
   • %ProgramFiles%CoolWebSearch
   • %ProgramFiles%SeX
   • %ProgramFiles%AntiVirus
   • %ProgramFiles%WINDOWS
     
     Note: %ProgramFiles% is a variable that refers to the program files folder. By default, this is C:Program Files.
     
     
3. Attempts to end the following processes using the TSKILL utility:
   • taskmgr
   • msconfig
   • ICQ
   • ICQLite
   • NISUM
   • NISSERV
   • guard
   • zonealarm
   • outpost
   • ad-aware
   • nmain
     
     
4. Adds the value:
   
   "nMain" = "%windir%winlogon32.bat"
   
   
   to the following registry key, so that the worm runs when Windows starts:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
   
   
5. Adds the value:
   
   "aUpdate32" = "%Windir%winlogon32.bat"
   
   
   to the following registry key:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun
   
   
6. Modifies or creates the following files, so that a copy of the worm is sent to other MIRC users:
   • %ProgramFiles%mIRCmirc.ini
   • %ProgramFiles%mIRCeventz.ini
     
     
7. Modifies the %Windir%Win.ini file so that the worm will run when Windows starts.
   
   
8. Overwrites all .pif files in the %Windir%System32 folder with a copy of itself.
   
   
9. Deletes all files that have the extension .mp3 in the current folder.

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
2. Update the virus definitions.
3. Run a full system scan and delete any files detected as BAT.Igador.
4. Edit the Win.ini file.
5. Edit the Mirc.ini file.
6. Delete specified lines from Win.ini [rfiles] section.
7. Delete the values from 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 have completed the removal procedure and are satisfied that the threat has been removed, re-enable System Restore by following the instructions in the previously mentioned 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:

• Run 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).
• Download 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 files.
   • For Norton AntiVirus consumer products, read "How to configure Norton AntiVirus to scan all files."
   • For Symantec AntiVirus Enterprise products, read "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 BAT.Igador, 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 "How to start the computer in Safe Mode." After you have restarted the computer in Safe mode, run the scan again.
   
   After you delete the files, you may leave the computer in Safe mode and proceed with section 4. After you have completed step 4, restart the computer in Normal mode.
   
   

4. To edit the Win.ini file in Windows 95/98/Me

1. On the Windows taskbar, click Start > Run.
2. Type the following:
   
   edit c:windowswin.ini
   
   
3. Click OK.
   The MS-DOS Editor opens.
   
   NOTE: If Windows is installed in a different location, make the appropriate path substitution.
   
   
4. In the [windows] section of the file, look for a line that is similar to one of the following:
   
   load=%systemroot%system32mirc.bat
   run=%systemroot%system32mirc.bat
   
   
5. If this line exists, delete everything to the right of load= or run=.
   
   
6. Click File > Save.
7. Click File > Exit.

5. To edit the mirc.ini file

1. Open the file %ProgramFiles%mIRCmirc.ini using a text editor.
2. Under the [afiles] section, delete the following lines:
   
   n0=aliases.ini
   n1=eventz.ini
   

6. To delete specified lines from Wini.ini [rfiles] section
Under the Wini.ini [rfiles] section, delete the following lines:

n0=remote.ini
n1=remote.ini
n2=eventz.ini

7. 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. On the Windows taskbar, click Start > Run.
2. Type the following:
   
   regedit
   
   
3. Click OK.
   
   
4. Navigate to the following key:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
   
5. In the right pane, delete the following value:
   
   "nMain" = "%windir%winlogon32.bat"
   
   
6. Navigate to the following key:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun
   
   
7. In the right pane, delete the following value:
   
   "aUpdate32" = "%Windir%winlogon32.bat"
   
   
8. Exit the Registry Editor.