Malware authors are increasingly using search engines and social networks to spread their wares and are relying less on email, according to a report published yesterday.

In its new "2010 Annual Security Report," Barracuda Networks says spam dropped by half during 2010, while search engine malware doubled.

The Twitter Crime Rate -- the percentage of accounts created per month that are eventually suspended by Twitter -- increased 20 percent in 2010, Barracuda says, "signifying a concentrated focus on the more lucrative social networks and search engines as attack vectors."

"The shift from email to search engines and social networks changes the way we think about security because the user no longer has to do something -- like click on an attachment -- to be infected," said Paul Judge, chief research officer at Barracuda Networks, in an interview at the RSA 2011 conference last month. "You can't just blacklist the known malicious sites. Your [antivirus] software may not look for iFrames that can lead to infection."

To help users fight infection on social networks, Barracuda Networks yesterday rolled out a free service, Profile Protector, which helps detect malicious threats on Facebook and Twitter.

According to the study, attackers have increased the spread of search engine malware and expanded their reach beyond Google. In June 2010, Google was crowned king of malware, turning up more than twice the amount of malware as Bing, Twitter, and Yahoo! combined, the report says. But by December 2010, with Google producing 38 percent of overall malware, Yahoo! was at 30 percent, Bing at 24 percent, and Twitter at 8 percent.

The amount of malware found daily across the search engines increased 55 percent between June and December, Barracuda says. One in five search topics leads to malware, while one in 1,000 search results leads to malware.

Barracuda Labs also analyzed more than 26 million Twitter accounts in order to measure and analyze account behavior. The number of true Twitter users -- those with more than 10 followers and friends -- increased to 43 percent in the second half, up from only 29 percent in June 2010.

For every 100 Twitter users, 39 have between one and nine followers, while 50 have more than 10 followers. Approximately 79 percent of Twitter users tweet less than once per day, the report says.

After decreasing at the end of 2009, the Twitter Crime Rate increased 20 percent from the first half of 2010 to the second half of 2010, going from 1.6 percent to 2 percent, Barracuda Networks says.

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