How to remove Trojan:JS/Medfos.B malware (Virus Removal Guide)

Trojan:JS/Medfos.B is a malicious JavaScript file that redirects search queries when using websites such as AOL, Ask, Bing, Google and Yahoo to other website from which cyber criminals get some sort of revenue.
Medfos is a member of the Win32/Medfos family and got your computer, after you have visited an infected website which exploited a vulnerability from a Java or Adobe software and Medfos installed a file called chromeupdate.crx in your %LOCALAPPDATA% folder.

As part of its self-defense mechanism,once installed Medfos disguises itself as a legitimate Google Chrome or Firefox extension with the name ChromeUpdateManager 1.0 or Translate This 2.0, as show in the below images:

Trojan:JS/Medfos.B sole purpose is to generate revenue for its authors via pay-per-click advertising links and redirect traffic to affiliate sites, so we recommend that you remove this Trojan as soon as possible from your computer.

Files reported as Trojan:JS/Medfos.B may not necessarily be malicious. Should you be uncertain as to whether a file has been reported correctly, you can submit the affected file to https://www.virustotal.com/en/ to be scanned with multiple antivirus engines.

You should always pay attention when installing software because often, a software installer includes optional installs. Be very careful what you agree to install.
Always opt for the custom installation and deselect anything that is not familiar, especially optional software that you never wanted to download and install in the first place. It goes without saying that you should not install software that you don’t trust.

How to remove Trojan:JS/Medfos.B virus (Virus Removal Guide)

This malware removal guide may appear overwhelming due to the amount of the steps and numerous programs that are being used. We have only written it this way to provide clear, detailed, and easy to understand instructions that anyone can use to remove malware for free.
Please perform all the steps in the correct order. If you have any questions or doubt at any point, STOP and ask for our assistance.

To remove Trojan:JS/Medfos.B virus, follow these steps:
STEP 1: Use Zemana AntiMalware Portable to remove malware
STEP 2: Scan and clean your computer with Malwarebytes Anti-Malware
STEP 3: Double-check for malicious programs with HitmanPro

STEP 1: Use Zemana AntiMalware Portable to remove malware

Zemana AntiMalware Portable is a free utility that will scan your computer for the Trojan:JS/Medfos.B browser hijacker and other malicious programs.

You can download Zemana AntiMalware Portable from the below link:
ZEMANA ANTIMALWARE PORTABLE DOWNLOAD LINK (This link will open a new web page from where you can download “Zemana AntiMalware Portable”)
Double-click on the file named “Zemana.AntiMalware.Portable” to perform a system scan with Zemana AntiMalware Free.

You may be presented with a User Account Control dialog asking you if you want to run this program. If this happens, you should click “Yes” to allow Zemana AntiMalware to run.
When Zemana AntiMalware will start, click on the “Scan” button to perform a system scan.
Zemana AntiMalware will now scan your computer for malicious programs. This process can take up to 10 minutes.
When Zemana has finished finished scanning it will show a screen that displays any malware that has been detected. To remove all the malicious files, click on the “Next” button.

Zemana AntiMalware will now start to remove all the malicious programs from your computer. When the process is complete, you can close Zemana AntiMalware and continue with the rest of the instructions.

STEP 2: Scan and clean your computer with Malwarebytes Anti-Malware

Malwarebytes Anti-Malware is a powerful on-demand scanner which should remove the Trojan:JS/Medfos.B virus from your machine. It is important to note that Malwarebytes Anti-Malware will run alongside antivirus software without conflicts.

You can download download Malwarebytes Anti-Malware from the below link.
MALWAREBYTES ANTI-MALWARE DOWNLOAD LINK (This link open a new page from where you can download “Malwarebytes Anti-Malware”)
When Malwarebytes has finished downloading, double-click on the “mb3-setup-consumer” file to install Malwarebytes Anti-Malware on your computer.

You may be presented with an User Account Control pop-up asking if you want to allow Malwarebytes to make changes to your device. If this happens, you should click “Yes” to continue with the installation.
When the Malwarebytes installation begins, you will see the Malwarebytes Setup Wizard which will guide you through the installation process.

To install Malwarebytes Anti-Malware on your machine, keep following the prompts by clicking the “Next” button.
Once installed, Malwarebytes will automatically start and update the antivirus database. To start a system scan you can click on the “Scan Now” button.
Malwarebytes Anti-Malware will now start scanning your computer for malicious programs.
This process can take a few minutes, so we suggest you do something else and periodically check on the status of the scan to see when it is finished.
When the scan has completed, you will be presented with a screen showing the malware infections that Malwarebytes Anti-Malware has detected.
To remove the malicious programs that Malwarebytes has found, click on the “Quarantine Selected” button.
Malwarebytes Anti-Malware will now quarantine all the malicious files and registry keys that it has found.
To complete the malware removal process, Malwarebytes may ask you to restart your computer.

When the malware removal process is complete, you can close Malwarebytes Anti-Malware and continue with the rest of the instructions.

STEP 3: Double-check for malicious programs with HitmanPro

HitmanPro can find and remove malware, adware, bots, and other threats that even the best antivirus suite can oftentimes miss. HitmanPro is designed to run alongside your antivirus suite, firewall, and other security tools.

You can download HitmanPro from the below link:
HITMANPRO DOWNLOAD LINK (This link will open a new web page from where you can download “HitmanPro”)
When HitmanPro has finished downloading, double-click on the “hitmanpro” file to install this program on your computer.

You may be presented with an User Account Control pop-up asking if you want to allow HitmanPro to make changes to your device. If this happens, you should click “Yes” to continue with the installation.
When the program starts you will be presented with the start screen as shown below. Now click on the Next button to continue with the scan process.
HitmanPro will now begin to scan your computer for malware.
When it has finished it will display a list of all the malware that the program found as shown in the image below. Click on the “Next” button, to remove malware.
Click on the “Activate free license” button to begin the free 30 days trial, and remove all the malicious files from your computer.

When the process is complete, you can close HitmanPro and continue with the rest of the instructions.

Your computer should now be free of the Trojan:JS/Medfos.B virus. If you are still experiencing problems while trying to remove Trojan:JS/Medfos.B virus from your machine, you can ask for help in our Malware Removal Assistance forum.