Discovered: October 10, 2004
Updated: February 13, 2007 12:28:14 PM
Also Known As: IRC-Worm.BAT.Igador [Kaspersky, BAT/Igador.A [McAfee]
Type: Trojan Horse
Systems Affected: Windows

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

Antivirus Protection Dates

  • Initial Rapid Release version October 11, 2004
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version October 11, 2004
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date October 12, 2004

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Writeup By: Rodney Andres

Discovered: October 10, 2004
Updated: February 13, 2007 12:28:14 PM
Also Known As: IRC-Worm.BAT.Igador [Kaspersky, BAT/Igador.A [McAfee]
Type: Trojan Horse
Systems Affected: Windows

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%\nmain97.bat
    • %Windir%\system32\ntscript.bat
    • %Windir%\system32\horse.exe
    • %Windir%\system32\mirc.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
    • 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:


  5. Adds the value:

    "aUpdate32" = "%Windir%\winlogon32.bat"

    to the following registry key:


  6. Modifies or creates the following files, so that a copy of the worm is sent to other MIRC users:
    • %ProgramFiles%\mIRC\mirc.ini
    • %ProgramFiles%\mIRC\eventz.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.


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.

Writeup By: Rodney Andres

Discovered: October 10, 2004
Updated: February 13, 2007 12:28:14 PM
Also Known As: IRC-Worm.BAT.Igador [Kaspersky, BAT/Igador.A [McAfee]
Type: Trojan Horse
Systems Affected: Windows

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:

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:
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.
  2. Run a full system scan.
  3. If any files are detected as infected with BAT.Igador, click Delete.

    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:\windows\win.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:


  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%\mIRC\mirc.ini using a text editor.
  2. Under the [afiles] section, delete the following lines:

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

7. To delete the value from the registry

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:


  3. Click OK.

  4. Navigate to the following key:


  5. In the right pane, delete the following value:

    "nMain" = "%windir%\winlogon32.bat"

  6. Navigate to the following key:


  7. In the right pane, delete the following value:

    "aUpdate32" = "%Windir%\winlogon32.bat"

  8. Exit the Registry Editor.

Writeup By: Rodney Andres