Believe it or not, this alarming, full screen pop-up is an ad. Or at least, it started as one. We had several questions about this very piece of 'scareware' last week.
Scareware is a type of scam which uses shock, fear, or anxiety to induce a panic reaction in a User, reducing their hesitation and reservations. Basically, a state of 'freak-out', which is not conducive to good decision making. Happily, several of our usual clients closed the lid and came directly to us, rather than calling the number on the screen (which you might notice is listed a suspicious 3 times).
It seemed like Users didn't even need to click on it for it to appear to take over their whole computer. One User who came to see us actually called the phone number (which I have blanked out for obvious reasons) and spoke to a real person who tried to sell them assistance in getting rid of this apparent Trojan Horse infection. The reality was that there was no infection, and this very aggressive pop-up was a phishing exercise. Happily, that User hung up before providing their credit card details.
Free services like Facebook sell advertising space on their pages in order to garner revenue since they don't charge Users for their primary service. This 'ad' managed to evade Facebook's notice and scare the heck out of many Facebook Users, probably successfully scamming some of them out of their money. I haven't seen any more incidents of this particular piece of scareware this week so I hope Facebook have now figured it out, but it goes to show that even a very common website that many people use all the time can be host to these malicious attacks. The way we dealt with this was by using an ad-blocker, but I'll admit, it does sometimes feel like a game of whack-a-mole with these security threats. Anti-virus software wasn't picking it up because it's an ad from a website. Ironically, if it had been a genuine Trojan Horse infection, it might have been less of a problem.