Trojan:W32/Fixer

Classification

Malware

Trojan

W32

Trojan:W32/Fixer, Trojan-Ransom.Win32.Fixer.a, Trojan.Generic.1582276

Summary

Trojan:W32/Fixer is a malicious program that demands a ransom from the user by encrypting and disabling documents and media files. The only way to decrypt the files is by purchasing a program being offered by the malware author(s). As such, this malware is a type of ransomware. The details below apply to the Trojan:W32/Fixer.A variant.

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 trojan's main component is a DLL that is dropped to:

  • %system%\fpfstb.dll

This DLL is injected into almost all running processes. It is not injected into some executables, including:

  • smss.exe
  • csrss.exe
  • winlogon.exe

It adds a launchpoint in the registry as below:

  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows AppInit_DLLs = "%system%\fpfstb.dll"

It creates these registries probably as infection markers:

  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\WOW\keyboard is_installed = [random string]
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\WOW\keyboard id = [random string]

Activity

Once installed, the DLL encrypts files with the following extensions to disable them :

  • ppsm
  • ppsx
  • ppam
  • potm
  • potx
  • pptm
  • pptx
  • xlam
  • xlsb
  • xltm
  • xltx
  • xlsm
  • xlsx
  • dotm
  • dotx
  • docm
  • docx
  • pst
  • mdb
  • wma
  • mp3
  • png
  • jpeg
  • jpg
  • pdf
  • ppt
  • xls
  • doc

Any newly created files on the system that use one of the extensions listed above are also encrypted.When user tries to open the encrypted files a screen like below is shown:

It also shows a popup like below at the bottom right corner on the system tray :

The only way for users to fix the so-called corrupted files is to purchase the FileFixPro program. If the "repair file" option is selected, user will be directed to this site:

  • https://www.filefixpro.com/[...]/download.php

The downloaded program is a scanner that will show a screen like below: