Now security researchers at Blue Coat say that they have seen CryptoWall being spread via ads.yahoo.com – a major online advertising network run by, yes you guessed it, Yahoo.Innocent computer users click on an advert served up by ad networks, which takes their browser leapfrogging from website to website, until they eventually arrive at a server containing an exploit kit designed to infect the PC with CryptoWall.“What looked like a minor malvertising attack quickly became more significant as the cybercriminals were successfully able to gain the trust of the major ad networks like ads.yahoo.com,” said Chris Larsen of Blue Coat Systems. “The interconnected nature of ad servers and the ease with which would-be-attackers can build trust to deliver malicious ads points to a broken security model that leaves users exposed to the types of ransomware and other malware that can steal personal, financial and credential information.”
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