I was on a Facebook page and I accidentally clicked an ad. Another window opened up and locked the browser with a background audio message, purportedly from Microsoft, warning about security compromise on my PC.

I unplugged my PC, restarted it, and it was working fine but found that history had been wiped in both IE and Firefox. I ran McAfee, Avast, Fortinet and Malwarebytes but they did not detect anything.

Is it possible there may still be some virus sitting in the system and evading detection by antivirus programs?

  • Wait, what? You still use IE?
    – nobody
    Commented Jul 19, 2021 at 11:01

4 Answers 4


It's possible, but if the virus infected a lot of computers from Facebook, the anti virus companies would probably recognize it eventually and issue a fix for it.


Just to make sure you're aware, that prompt was most likely only trying to scare you into calling their fake support number. If they wanted to infect you with malware, they wouldn't be wise to announce it to you.

Technically yes, it's possible you could have some malware still on your PC that your software missed. Thing is, it's difficult to prove a negative, so authoritatively proving you're clean is difficult. You'd have to perform very skillful and tedious analysis to find something these scanners missed. If you're truly concerned you may be compromised, format your PC and reinstall your OS.


There are 2 possibilities in this scenerio:

  • There is a technique called Process injection used for running code within the address space of another process by forcing it to load a dynamic-link library. In simple terms it means hijacking a process and injecting shellcode (malicious code) into that but the disadvantage of such malware is it gets wiped out as soon as the PC restarts. Such types of malware cannot be detected easily by Anti Virus softwares.

  • Another is adware, its a software that displays unwanted (and sometimes irritating) pop-up adverts which can appear on your computer or mobile device. It works by installing itself quietly onto your device, hoping you’ll – accidentally or otherwise – click on an advert that it displays to you. It is mainly used to generate revenue for the developers by displaying advertisements which means adware can also track your search and browsing history to display ads that are more relevant to you. Once the developer has your location and browser history, they can make additional income by selling that information to third parties. This article provides a good insight on such malware.


I know this is not the answer your looking for, but that answer is the not going to help you. This is not a virus, it is a browser redirect. It causes big problems because users freak out, and do exactly what you did, wind up spending money trying to detect a problem that does not exist, thinking it must exist because they knew something bad that only Microsoft could know! One detection failure leads to many tools battling for your systems resources which, cause your system to run slow, and soon re-installing the OS seems the only way out. The good news is you did not call them, and give a tech support scammer remote access, or your credit card to fix this.

Facebook verifies an ad's content will not cause problems. But after the ad is verified, the traffic is either redirected, or changed to cause your browser to block you from using your mouse on the page (very basic explanation).

They use information from your advertising ID to know what your interests are, and generate this stuff accordingly. Also in Facebook it may just be you belong to a group that market research suggests would be interested in adult-based ads because your friends are.

The bottom line is no virus detection will ever find this, and re-installing your OS will not change your browsing behavior. The best thing is to know Microsoft does not do this, the FBI would just arrest you, if you did something seriously illegal and you are in the US, and any message demanding money in exchange for not causing you any embarrassment or harm is illegal.

Also, just knowing what this is should be enough next time. It is browser redirect, plain and simple.

  • It is not that simple. These redirects can also try to exploit your browser and infect your machine.
    – schroeder
    Commented Jul 19, 2021 at 10:53
  • The fact that the user says his entire history for both his browsers was cleared indicates something else. There's no way for an unprivileged process to clear the entire browser history. The window.history calls only allow for modification of the current URL. So either OP's entire history wasn't cleared, or it certainly wasn't "just" a redirect.
    – Nomad
    Commented Jul 19, 2021 at 14:25

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .