OS Firewall is a scareware program from the Trojan.Tech-Support-Scam family that displays fake security alerts that state your computer is infected and then prompts you to call the 1-855-270-1376 remote tech support number. These alerts are worded to scare you into thinking your computer has a problem so that you call the listed number. These telephone numbers, though, are for remote support companies who will try to sell you unnecessary support services or software.
When OSFirewall is installed it will be copied into %AppData%\Microsoft\OSFirewall.exe and will display a constant stream of fake security warnings. These security warnings state that a virus has been detected or that there is suspicious activity found on your computer. The text of these alerts is:
Suspicious Activity Found
During a routine scan, We've found a possible virus, we cannot automatically remove. Please call the number listed below to get step by step guidance to secure your computer.
Call Now: +1-855-270-1376
Another alert that is displayed will contain the following message:
We Cannot Remove This Virus Automatically. Please Call Right Away
It is important to note that the OS Firewall is is installed by free programs that you download from the Internet, which did not adequately disclose that other software would be installed along with it. Therefore, it is important that you pay close attention to license agreements and installation screens when installing anything off of the Internet. If an installation screen offers you Custom or Advanced installation options, it is a good idea to select these as they will typically disclose what other 3rd party software will also be installed. Furthermore, If the license agreement or installation screens state that they are going to install a toolbar or other unwanted adware, it is advised that you immediately cancel the install and not use the free software.
As you can see, this infections is designed purely to scare you into calling the remote support number so that they can sell you technical support services. It is strongly advised that you do not call the number, and if you already have called them and paid for services, to contact your credit card provider to dispute the charges. To remove the OS Firewall scareware and related programs, please you use the removal guide below to remove it and other related programs for free.
Self Help Guide
If you are uncomfortable making changes to your computer or following these steps, do not worry! Instead you can get free one-on-one help by asking in the forums.
To remove OS Firewall, follow these steps:
- STEP 1: Print out instructions before we begin.
- STEP 2: Use Rkill to terminate suspicious programs.
- STEP 3: Use Malwarebytes AntiMalware to Scan for Malware and Unwanted Programs
- STEP 4: Use AdwCleaner to remove adware from a computer.
- STEP 5: Use HitmanPro to scan your computer for badware
- STEP 6: Run Secunia PSI to find outdated and vulnerable programs.
This removal guide may appear overwhelming due to the amount of the steps and numerous programs that will be used. It was only written this way to provide clear, detailed, and easy to understand instructions that anyone can use to remove this infection for free. Before using this guide, we suggest that you read it once and download all necessary tools to your desktop. After doing so, please print this page as you may need to close your browser window or reboot your computer.
To terminate any programs that may interfere with the removal process we must first download the Rkill program. Rkill will search your computer for active malware infections and attempt to terminate them so that they wont interfere with the removal process. To do this, please download RKill to your desktop from the following link.
When at the download page, click on the Download Now button labeled iExplore.exe. When you are prompted where to save it, please save it on your desktop.
Once it is downloaded, double-click on the iExplore.exe icon in order to automatically attempt to stop any processes associated with OS Firewall and other malware. Please be patient while the program looks for various malware programs and ends them. When it has finished, the black window will automatically close and a log file will open. Please review the log file and then close so you can continue with the next step. If you have problems running RKill, you can download the other renamed versions of RKill from the rkill download page. All of the files are renamed copies of RKill, which you can try instead. Please note that the download page will open in a new browser window or tab.
Do not reboot your computer after running RKill as the malware programs will start again.
At this point you should download Malwarebytes Anti-Malware, or MBAM, to scan your computer for any infections, adware, or potentially unwanted programs that may be present. Please download Malwarebytes from the following location and save it to your desktop:
Once downloaded, close all programs and Windows on your computer, including this one.
Double-click on the icon on your desktop named mb3-setup-1878.1878-18.104.22.1687.exe. This will start the installation of MBAM onto your computer.
When the installation begins, keep following the prompts in order to continue with the installation process. Do not make any changes to default settings and when the program has finished installing, make sure you leave Launch Malwarebytes Anti-Malware checked. Then click on the Finish button. If MalwareBytes prompts you to reboot, please do not do so.
MBAM will now start and you will be at the main screen as shown below.
We now need to enable rootkit scanning to detect the largest amount of malware and unwanted programs that is possible with MalwareBytes. To do this, click on the Settings button on the left side of the screen and you will be brought to the general settings section.
Now click on the Protection tab at the top of the screen. You will now be shown the settings MalwareBytes will use when scanning your computer.
At this screen, please enable the Scan for rootkits setting by clicking on the toggle switch so it turns green.
Now that you have enabled rootkit scanning, click on the Scan button to go to the scan screen.
Make sure Threat Scan is selected and then click on the Start Scan button. If there is an update available for Malwarebytes it will automatically download and install it before performing the scan.
MBAM will now start scanning your computer for malware. This process can take quite a while, so we suggest you do something else and periodically check on the status of the scan to see when it is finished.
When MBAM is finished scanning it will display a screen that displays any malware, adware, or potentially unwanted programs that it has detected. Please note that the items found may be different than what is shown in the image below due to the guide being updated for newer versions of MBAM.
You should now click on the Remove Selected button to remove all the selected items. MBAM will now delete all of the files and registry keys and add them to the programs quarantine. When removing the files, MBAM may require a reboot in order to remove some of them. If it displays a message stating that it needs to reboot, please allow it to do so. Once your computer has rebooted, and you are logged in, please continue with the rest of the steps.
You can now exit the MBAM program.
Now please download AdwCleaner and save it to your desktop. AdwCleaner will scan your computer for adware programs that may have been installed on your computer without your knowledge. You can download AdwCleaner from the following URL:
When AdwCleaner has finished downloading, please double-click on the AdwCleaner.exe icon that now appears on your desktop. Once you double-click on the icon the AdwCleaner program will open and you will be presented with the program's license agreement. After you read it, click on the I agree button if you wish to continue. Otherwise, click on the I disagree button to close the program. If Windows prompts you as to whether or not you wish to run AdwCleaner, please allow it to run.
If you selected to continue, you will be presented with the start screen as shown below.
Now click on the Scan button in AdwCleaner. The program will now start to search for known adware programs that may be installed on your computer. When it has finished it will display all of the items it has found in Results section of the screen above. Please look through the results and try to determine if the programs that are listed contain ones that you do not want installed. If you find programs that you need to keep, then uncheck the entries associated with them.
For many people, the contents of the Results section may appear confusing. Unless you see a program name that you know should not be removed,please continue with the next step.
To remove the adware programs that were detected in the previous step, please click on the Clean button on the AdwCleaner screen. AdwCleaner will now prompt you to save any open files or data as the program will need to close any open programs before it starts to clean.
Please save your work and then click on the OK button. AdwCleaner will now delete all detected adware from your computer. When it is done it will display an alert that explains what PUPs (Potentially Unwanted Programs) and Adware are. Please read through this information and then press the OK button. You will now be presented with an alert that states AdwCleaner needs to reboot your computer.
Please click on the OK button to let AdwCleaner reboot your computer.
When your computer reboots and you are logged in, AdwCleaner will automatically open a log file that contains the files, registry keys, and programs that were removed from your computer.
Please review this log file and then close the Notepad Window.
Now you should download HitmanPro from the following location and save it to your desktop:
When you visit the above page, please download the version that corresponds to the bit-type of the Windows version you are using.
Once downloaded, double-click on the file named HitmanPro.exe (for 32-bit versions of Windows) or HitmanPro_x64.exe (for 64-bit versions of Windows). 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.
You will now be at the HitmanPro setup screen. If you would like to install the 30 day trial for HitmanPro, select the Yes, create a copy of HitmanPro so I can regularly scan this computer (recommended) option. Otherwise, if you just want to scan the computer this one time, please select the No, I only want to perform a one-time scan to check this computer option.
Once you have selected one of the options, please click on the Next button.
HitmanPro will now begin to scan your computer for infections, adware, and potentially unwanted programs. When it has finished it will display a list of all the items that Hitman has found as shown in the image below. Please note that the items found may be different than what is shown in the image.
You should now click on the Next button to have HitmanPro remove the detected items. When it is done you will be shown a Removal Results screen that shows the status of the various programs that were removed. At this screen you should click on the Next button and then if prompted you should click on the Reboot button. If HitmanPro does not prompt you to reboot, please just click on the Close button.
Once your computer has has restarted or you pressed the Close button, you should now be at your Windows desktop.
As many malware and unwanted programs are installed through vulnerabilities found in out-dated and insecure programs, it is strongly suggested that you use Secunia PSI to scan for vulnerable programs on your computer. A tutorial on how to use Secunia PSI to scan for vulnerable programs can be found here:
Your computer should now be free of the OS Firewall program. If your current security solution allowed this program on your computer, you may want to consider purchasing the full-featured version of Malwarebytes Anti-Malware to protect against these types of threats in the future.
If you are still having problems with your computer after completing these instructions, then please follow the steps outlined in the topic linked below:
Are Your Protected?
While Malwarebytes Anti-Malware & HitmanPro will scan and clean a computer for free, the free versions do not offer real-time protection. If you want to be fully protected at all times then it is recommended that you purchase a premium version.
Purchase the full-featured version of Malwarebytes Anti-Malware, which includes real-time protection, scheduled scanning, and website filtering, to protect yourself against these types of threats in the future!
Purchase the full-featured version of HitmanPro, which includes discover viruses, trojans, rootkits, spyware and other malware on up-to-date and fully protected computers using cloud protection and behavioral detections, to protect yourself against these types of threats in the future!
Disclaimer: While we do earn a commission from the sale of the above products, rest assured we only recommend them due to their effectiveness.