W32.Gokar.A@mm

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Discovered: December 12, 2001
Updated: February 13, 2007 11:49:49 AM
Also Known As: I-Worm.Gokar [Kaspersky], W32/Gokar-A [Sophos], W32/Gokar@MM [McAfee], WORM_GOKAR.A [Trend], Win32.Gokar [Computer Associat
Type: Worm
Systems Affected: Windows


This worm will send itself as an attachment to all addresses in your Microsoft Outlook address book. It also will create an mIRC Script.ini file and an inetpub Default.htm file to try to spread itself.

Antivirus Protection Dates

  • Initial Rapid Release version December 13, 2001
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version December 13, 2001
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date December 13, 2001

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


Technical Description


When executed, the worm does the following:

It creates a email with the following characteristics:

Subject: The subject is one of the following:

  • If I were God and didn't belive in myself would it be blasphemy
  • The A-Team VS KnightRider ... who would win ?
  • Just one kiss, will make it better. just one kiss, and we will be alright.
  • I can't help this longing, comfort me.
  • And I miss you most of all, my darling ...
  • ... When autumn leaves start to fall
  • It's dark in here, you can feel it all around. The underground.
  • I will always be with you sometimes black sometimes white ...
  • .. and there's no need to be scared, you re always on my mind.
  • You just take a giant step, one step higher.
  • The air will hold you if you try, trust my wings of desire. Glory, Glorified.......

Message: The text of the message is one of the following:
  • Happy Birthday
  • Yeah ok, so it's not yours it's mine :)
  • The horizons lean forward, offering us space to place new steps of change.
  • I like this calm, moments before the storm
  • Darling, when did you fall..when was it over ?
  • Will you meet me .... and we'll fly away ?!
  • You should like this, it could have been made for you
  • speak to you later
  • They say love is blind ... well, the attachment probably proves it.
  • Pretty good either way though, isn't it ?
  • still cause for a celebration though, check out the details I attached
  • This made me laugh
  • Got some more stuff to tell you later but I can't stop right now
  • so I'll email you later or give you a ring if thats ok ?!
  • Speak to you later
Attachment: The file name of the attachment consists a random number and some of these strings:

tgfdfg jhfxvc cgfd2 trevc t6tr ffdasf glkfh fhjdv qesac kujzv weafs twat rewfd gfdsf hgbv fdsc p0olik 3tgf rf43dr t54refd ut545a r4354gkjw vgrewu xw54re y343rv z3vdf
    with a file extension chosen from one of the following:
    • .pif
    • .scr
    • .exe
    • .com
    • .bat

    The worm then adds the mail user's name to the end of the message, and sends the mail to all addresses in your Microsoft Outlook address book.


    Next, it copies itself to the \Windows folder as Karen.exe.

    It then and adds the value

    Karen     c:\windows\karen.exe

    to the registry key

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

    This will cause the worm to be run on each time that you start Windows.

    It then looks for the C:\Mirc folder. If it exists, it creates the file Script.ini in that location, so that it will attempt to send itself through mIRC when mIRC is run.

    It also searches looks for the C:\inetpub\wwwroot folder, and, if found, it copies itself there as Web.exe. (This folder is found in Microsoft IIS web servers.) It then renames the Default.htm file to Redesi.htm, and it creates a new Default.htm file, which will display the text:

    We Are Forever

    Anyone who views this page will be asked to download the Web.exe file.

    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.


    Removal


    Delete files detected as W32.Gokar.A@mm, remove the value that it added to the registry, and if necessary, rename C:\inetpub\Wwwroot\Redesi.htm to C:\inetpub\Wwwroot\Default.htm

    To remove the worm files:

    1. Run LiveUpdate to make sure that you have the most recent virus definitions.
    2. Start Norton AntiVirus (NAV), and make sure that NAV is configured to scan all files. For instructions on how to do this, read the document How to configure Norton AntiVirus to scan all files.
    3. Run a full system scan.
    4. Delete all files that are detected as W32.Gokar.A@mm

    To edit the registry:

    CAUTION : We strongly recommend that you back up the system registry before you make any changes. Incorrect changes to the registry could result in permanent data loss or corrupted files. Please make sure that you modify only the keys that are specified. Please see the document How to back up the Windows registry before you proceed.
    1. Click Start, and click Run. The Run dialog box appears.
    2. Type regedit and then click OK. The Registry Editor opens.
    3. Navigate to the following key:

      HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    4. In the right pane, delete the following value:

      Karen     c:\windows\karen.exe
    5. Click Registry, and then click Exit

    To rename Redesi.htm:
    This only is necessary if you are running Microsoft IIS web servers software.
    1. Using Windows Explorer, browse to the C:\inetpub\wwwroot folder.
    2. Rename the Redesi.htm file back to Default.htm



    Writeup By: Dave Adamczyk