Google has cleaned up malware-serving domains that were turning up as highly ranked pages when searching for innocent terms, but as of Nov. 29 Yahoo was still crawling with it.
"I can find thousands of domains serving malware in a matter of seconds with very simple and legitimate searches," done through Yahoo search, Sunbelt Security researcher Francesco Benedini told eWEEK.
Sunbelt President Alex Eckelberry said that Google and Microsoft Live search both seem to have been cleaned up. But Yahoo only contacted Sunbelt to request a list of malware-serving domains on Nov. 29—a full four days after Sunbelt first discovered the infestation.
Sunbelt reported on Nov. 26 that malware, including malicious iFrames, rootkits and fake codecs, was being served up on tens of thousands of sites returned as results for searches on the three most popular search engines—Google, Yahoo and Microsoft Live—for such things as alternate router firmware or "how to for Microsoft Excel."
The malware-serving sites are filtering traffic by country, Benedini said. In the United States, the sites are serving fake security applications or fake codec malware, whereas in Italy theyre serving exploits to install dialers and rootkit-based malware.
For instance, on Nov. 29 Benedini searched for the word "giubbotto" (Italian for "jacket") in .info domains and found that nearly all of the sites returned by Yahoo redirect to malware.
Click here to read more about a malware blitz served up through DoubleClick.
Yahoo appears to have been hit less hard than Google in this most recent round of malware seeding. But that may be due to Google having more quickly indexed these particular malware domains, many of which were either Chinese or posing as Chinese domains, with .cn at their URL end.
Many of the bad domains showing up in Yahoo results have actually been serving malware for some time, Benedini said. But headlines related to the bad .cn domains likely lit a fire under Google, he said, given how quickly the company cleaned up.
"Google had more mess to clean up in the first place," Benedini said. "I dont recall Yahoo ever being particularly efficient in cleaning up results from bad domains; most of the ones I showed in the .info [top-level domain] are months old, and have been serving malware for months."
Sunbelt contacted Google about the malware-seeding issue on Nov. 26 and talked to Microsoft about it as well; Eckelberry said that the company has been working closely with Microsoft security response engineers on the problem.
Yahoo said in a statement that its "very serious about protecting its users from malicious sites on the Web."
The statement concluded by saying: "Malware is an ongoing battle for all search engines and Yahoo has processes in place to quickly remove these sites from its index."
Microsoft supplied a statement to the effect that it is aware of the issue, is working to rectify the situation and apologizes for the inconvenience. Google had not provided comment by the time this story posted.
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