Popular websites with millions of visitors are serving poisoned web ads.–PC Pitstop
Alert: Massive Web Ad Poisoning
By Stu Sjouwerman, for KnowBe4.com Security Awareness Training
The same cybercrime lowlifes that infected the Yahoo website a few weeks ago have struck again, this time infecting sites like Drudge Report and Weather.com. Both sites have hundreds of millions of visitors per month, and were serving poisoned web ads which either dropped CryptoWall ransomware or infected the PC with adware.
Internet users at the house, or employees who browse the web during their lunch break do not understand the mechanics of modern ad networks. Once an ad network is subverted, hundreds of millions of poisoned ads are displayed in real-time. Many of these ads initiate a drive-by attack without the user having to do anything. The attack does a few redirects, kicks in a U.S. and Canada-focused Exploit Kit which checks for vulnerabilities (usually in Flash) and infects the workstation literally in seconds.
What To Do About It
This is a hard one to defend against, because they hide behind an SSL to Microsoft’s Azure Cloud which makes it difficult to detect, but there are definitely things you can do. First of all, I would send this to your
users. Feel free to copy/paste/edit:
Scam of The Week Warning – you need to understand something about poisoned ads on websites which might infect your computer. Here is the situation in a nutshell: Advertisers do not sell their ads to websites one at a time. Websites that want to make money sell their advertising space to an ad network. Advertisers sign contracts with that ad network which then displays the ads on the participating websites. The ad network sits in the middle between the advertisers and the websites and manages the traffic and the payments.
And there is the problem.
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