1. Symantec/
  2. Security Response/
  3. W32.Gobot.A


Risk Level 2: Low

May 6, 2004
February 13, 2007 12:22:44 PM
Also Known As:
Backdoor.Gobot.u [Kaspersky], Exploit-Mydoom [McAfee]
Trojan Horse, Worm
Systems Affected:

When W32.Gobot.A is executed, it does the following,
  1. Copies itself to the %Windir% folder using a random file name.

    Note: %Windir% is a variable. The worm locates the Windows installation folder (by default, this is C:\Windows or C:\Winnt) and copies itself to that location.

  2. Adds a value:

    "<random value>"="%Windir%\<random filename>"

    to the registry key:


    so that the worm runs when you restart Windows.

  3. Terminates the processes of some popular antivirus and security applications.

  4. Attempts to connect to the C$ share of all available local network drives and copy itself as C:\Documents and Settings\All Users\Start Menu\Programs\Startup\!ReadMe.exe

  5. Attempts to send itself to any Mydoom backdoors that it finds.

  6. Copies itself to the shared folders of some popular file-sharing networks, such as Kazaa, Edonkey, Morpheus, XoloX, ShareAza, and LimeWire.

    For example, it may copy itself as any of the following files:
    • AIM_Account_Stealer_Crack.exe
    • AIM_Account_Stealer_Crack.exe
    • AIM_Account_Stealer_Full.exe
    • AIM_Account_Stealer_Full.exe
    • AIM_Account_Stealer_ISO_Full.exe
    • AIM_Account_Stealer_Key_Generator.exe
    • AIM_Account_Stealer_Patch.exe
    • AIM_Account_Stealer_Patch.exe
    • Cat_Attacks_Child_Crack.exe
    • Cat_Attacks_Child_Full.exe
    • Cat_Attacks_Child_ISO_Full.exe
    • Cat_Attacks_Child_ISO_Full.exe
    • Cat_Attacks_Child_Key_Generator.exe
    • Cat_Attacks_Child_Key_Generator.exe
    • Cat_Attacks_Child_Patch.exe
    • CKY3_Bam_Margera_World_Industries_Alien_Workshop_Crack.exe
    • CKY3_Bam_Margera_World_Industries_Alien_Workshop_Full.exe
    • CKY3_Bam_Margera_World_Industries_Alien_Workshop_ISO_Full.exe
    • CKY3_Bam_Margera_World_Industries_Alien_Workshop_Key_Generator.exe
    • CKY3_Bam_Margera_World_Industries_Alien_Workshop_Patch.exe
    • CKY3_Bam_Margera_World_Industries_Alien_Workshop_Patch.exe
    • DSL_Modem_Uncapper_Crack.exe
    • DSL_Modem_Uncapper_Crack.exe
    • DSL_Modem_Uncapper_Full.exe
    • DSL_Modem_Uncapper_Full.exe
    • DSL_Modem_Uncapper_ISO_Full.exe
    • DSL_Modem_Uncapper_ISO_Full.exe
    • DSL_Modem_Uncapper_Key_Generator.exe
    • DSL_Modem_Uncapper_Patch.exe
    • Hacking_Tool_Collection_Crack.exe
    • Hacking_Tool_Collection_Crack.exe
    • Hacking_Tool_Collection_Full.exe
    • Hacking_Tool_Collection_ISO_Full.exe
    • Hacking_Tool_Collection_Key_Generator.exe
    • Hacking_Tool_Collection_Patch.exe
    • Hacking_Tool_Collection_Patch.exe
    • Internet_and_Computer_Speed_Booster_Crack.exe
    • Internet_and_Computer_Speed_Booster_Crack.exe
    • Internet_and_Computer_Speed_Booster_Full.exe
    • Internet_and_Computer_Speed_Booster_ISO_Full.exe
    • Internet_and_Computer_Speed_Booster_Key_Generator.exe
    • Internet_and_Computer_Speed_Booster_Patch.exe
    • Macromedia_Flash_5.0_Crack.exe
    • Macromedia_Flash_5.0_Full.exe
    • Macromedia_Flash_5.0_ISO_Full.exe
    • Macromedia_Flash_5.0_ISO_Full.exe
    • Macromedia_Flash_5.0_Key_Generator.exe
    • Macromedia_Flash_5.0_Key_Generator.exe
    • Macromedia_Flash_5.0_Patch.exe
    • MSN_Password_Hacker_and_Stealer_Crack.exe
    • MSN_Password_Hacker_and_Stealer_Full.exe
    • MSN_Password_Hacker_and_Stealer_Full.exe
    • MSN_Password_Hacker_and_Stealer_ISO_Full.exe
    • MSN_Password_Hacker_and_Stealer_Key_Generator.exe
    • MSN_Password_Hacker_and_Stealer_Patch.exe
    • Windows_XP_Crack.exe
    • Windows_XP_Crack.exe
    • Windows_XP_Full.exe
    • Windows_XP_Full.exe
    • Windows_XP_ISO_Full.exe
    • Windows_XP_Key_Generator.exe
    • Windows_XP_Key_Generator.exe
    • Windows_XP_Patch.exe
    • ZoneAlarm_Firewall_Crack.exe
    • ZoneAlarm_Firewall_Full.exe
    • ZoneAlarm_Firewall_ISO_Full.exe
    • ZoneAlarm_Firewall_Patch.exe
    • ZoneAlarm_Firewall_Patch.exe

  7. May append itself to all .exe files in the shared folders of file-sharing programs.

  8. Connects to a predetermined IRC server and awaits commands from a remote attacker. This allows the attacker to perform the following actions on an infected system:
    • Run commands
    • Retrieve files via FTP and HTTP
    • Retrieve data from the registry
    • Restart the computer
    • List processes
    • Kill a particular process
    • Terminate Windows services
    • Perform HTTP, ICMP, SYN, and UDP floods
    • Retrieve email addresses stored on the computer
    • Retrieve a list of email addresses via HTTP
    • Retrieve given URLSniff HTTP, FTP, and IRC traffic
    • Steal the Windows product ID and the CD keys of various video games


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: Yana Liu
Summary| Technical Details| Removal

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