Girlgif.Trojan

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Discovered: November 15, 2001
Updated: February 13, 2007 11:49:32 AM
Type: Trojan Horse


Girlgif.Trojan is a Trojan horse that usually is sent by a hacker using email. The email message has two attachments: Girl.exe and Girl.gif. The Girl.gif file is actually a .dll file, not a .gif file.

Both of these files are packed using the Aspack utility. The file size of Girl.exe is 65 KB and Girl.gif is about 17 KB.

Antivirus Protection Dates

  • Initial Rapid Release version November 16, 2001
  • Latest Rapid Release version August 08, 2016 revision 023
  • Initial Daily Certified version November 16, 2001 revision 002
  • Latest Daily Certified version August 09, 2016 revision 001

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

Writeup By: Gor Nazaryan

Discovered: November 15, 2001
Updated: February 13, 2007 11:49:32 AM
Type: Trojan Horse


When Girl.exe is executed, it looks for the Girl.gif file in the same folder in which it resides. If it finds Girl.gif, it copies it to \Windows\System as Imnepr.dll. It then registers the Imnepr.dll file, and hooks the keyboard and Windows messages to track whatever you type or execute.

The Trojan might track passwords that you use to log in to specific locations. Some of the tracked keyboard and Windows messages are written to the \Windows\System\Systems.dat file. The Systems.dat file is a log file that is created by the Trojan. The Trojan may then attempt to send this log file to a hacker's email account in China; however, this email account is not currently active.

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.

Writeup By: Gor Nazaryan

Discovered: November 15, 2001
Updated: February 13, 2007 11:49:32 AM
Type: Trojan Horse


Please read entire removal procedure before you begin.

  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 Girlgif.Trojan.
  5. (Optional) Using Windows Explorer, delete the Systems.dat file from the \Windows\System folder.

    CAUTION: If this file exists, there will be two files with similar names:
    • Systems.dat: (Note the "s" at the end of Systems). This is the file that was added by the Trojan
    • System.dat: This is a legitimate, required Windows file that is part of the Windows registry.
Make sure that you delete the Systems .dat file. Do not delete System.dat.


Writeup By: Gor Nazaryan