Ginwui.A

Classification

Trojan

Backdoor

W32

Ginwui.A, W32/Ginwui.A, W32/Ginwui.A.dr, Backdoor.Ginwui

Summary

Ginwui is a fully featured backdoor with rootkit characteristics. This backdoor is distributed inside a Word document file with shell-code that drops the backdoor's file to the hard drive and activates it.

Removal

Automatic action

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

Suspect a file is incorrectly detected (a False Positive)?

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest detection database updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    NOTE If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note You need administrative rights to change the settings.

Find out more

Knowledge Base

Find the latest advice in our Community Knowledge Base.

User Guide

See the user guide for your product on the Help Center.

Contact Support

Chat with or call an expert for help.

Submit a sample

Submit a file or URL for further analysis.

Technical Details

The shell-code in the Word document decrypts and drops the backdoor's file as CSRSE.EXE to the system's temporary folder and activates it.

After being run, the dropped file in its turn extracts and drops another file to the system. This file is dropped as WINGUIS.DLL to Windows System folder and its DoHook function is activated by the dropper. The dropper then deletes itself from the system.

The dropped DLL file is the main backdoor component. It traps several functions and modifies information that is passed to the user. As a result, the backdoor's file, startup key in the Registry, and process are not visible to the user.

The backdoor creates a startup key for its file in the Registry:

  • [HKLM\Software\Microsoft\Windows NT\CurrentVersion\Windows]"AppInit_DLLs" = "%WinSysDir%\winguis.dll"

where %WinSysDir% represents the Windows System folder that by default has the name C:\Windows\System32\.

When active, the backdoor connects to a specified address in order to receive commands from a hacker. The backdoor allows the hacker to do any of the following on an infected computer:

  • Create, read, write, delete and search for files and directories
  • Access and modify the Registry
  • Manipulate services
  • Start and kill processes
  • Take screenshots
  • Enumerate open windows
  • Create its own application window
  • Get information about infected computer
  • Lock, restart or shutdown Windows
  • Create a pipe and read files from it
  • Start a remote command shell
  • Enumerate network resources

The backdoor also creates three empty SYS files in the \drivers\ subfolder of Windows System folder.