For a brief period this week, cybercriminals managed to infect Google and Microsoft online ad networks with malwares that attacked users' PCs. "The attacks started around Dec. 5 and lasted a few days, sending victims who clicked on the ads to malicious Web pages. Those pages took advantage of known software bugs to install backdoor programs that gave the attackers control of the victims' PCs, or to install software that made it appear as though the PCs were filled with malicious software," according to security consultancy Armorize.
Google on Friday acknowleged "[T]he DoubleClick Ad Exchange, which has automatic malware filters, independently detected several [ads] containing malware, and blocked them instantly -- within seconds," Google spokesman Jay Nancarrow said via email. "Our security team is in touch with Armorize to help investigate and help remove any affected creatives from any other ad platforms."
Armorize's Wayne Huang said cybercriminals may have tricked Google by serving the ads from a domain similar to that used by a legitimate ad-serving company, AdShuffle, based in Irving, Texas. AdShuffle couldn't be reached for comment Friday.
Armorize and others spotted similar ads on Microsoft's Hotmail service, according to Huang. Microsoft said via email that it was was looking into the matter and couldn't comment in time for this report.
The ads exploit bugs in Adobe Reader, Java and other PC software, Huang said. The bugs have been previously identified, which means people with up-to-date software and antivirus products shouldn't be at risk.