Out of the top five search engines, Yahoo returns the riskiest sites for users, according to security vendor McAfee.
In research published on Monday by McAfee SiteAdvisor, 5.4 percent of Yahoo searches returned links to "risky" internet sites. AOL was found to be the safest of the top five, with 2.9 percent of sites.
According to McAfee SiteAdvisor, Yahoo returned the most results rated "red" or "yellow". "Red" rated sites failed McAfee SiteAdvisor's safety tests. "Examples are sites that distribute adware, send a high volume of spam, or make unauthorised changes to a user's computer," said the report. Examples of "Yellow" rated sites are those which send a high volume of "non-spammy" email, display many pop-up ads, or prompt a user to change browser settings.
According to McAfee, overall, on Yahoo, MSN, Ask.com, Google, and AOL, sponsored searches returned more risky results than "organic" searches. Of sponsored searches, 6.9 percent returned risky content, compared with 2.9 percent of organic searches.
McAfee analyst Greg Day told ZDNet.co.uk that those wishing to make money from the spread of malicious code were willing to pay search companies, or try to trick them, to boost malicious ad rankings and increase the chance of click-throughs to malicious sites. "The simple reality is that, if you want to make money, you get to know how to trick search engines to get to the top [rankings], or you pay your way to get to the top," said Day. "On the straight figures, Yahoo is the highest level risky site."
McAfee stopped short of recommending that IT managers discourage company employees from using Yahoo search, but did say that the search company should employ more rigorous analysis of the content of sites returned by its search. "Google is starting to go away and do analysis of whether [site] content is what it claims to be. Yahoo really has to go down that road."
Yahoo said it already has a rigorous editorial policy on sites displayed by its search results, especially for sponsored results.
Reggie Davis, vice president of marketplace quality at Yahoo, told ZDNet.co.uk: "We have strict editorial policies in place, conduct ongoing editorial review and employ teams of product experts, engineers and analysts focused on ensuring and continually enhancing the relevancy of our sponsored search ads."
Davis did not seek to refute the McAfee SiteAdvisor research, or its ranking of Yahoo as the most risky search company of the top five. Instead, he stated: "Yahoo has been a strong proponent of helping fight malware, and is, in fact, the only major search vendor who makes free anti-spyware software available to its users. We support any efforts that help with the ongoing fight against unsafe sites."
Davis said that, according to the McAfee research, Yahoo's organic search results, "which represent the vast majority of clicked links for consumers, have the highest safety and quality rating of all major search vendors".
According to Davis, it is not in Yahoo's interest "to deliver experiences that would erode the trust of our users and advertisers, as we are committed to building the world's highest-quality online advertising marketplace and providing the safest and most relevant search experience possible for our users".
"We will continue to improve our performance in this area by investing in technology and work with third parties to make the internet safe for consumers," Davis added.