Slideshow: Top 10 Tech Newsmakers Of 2010
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The tweet in question turned out to be an attack that "spread vulgar messages [about goats] from many affected users' accounts" -- said Graham Cluley, senior technology consultant at Sophos.
That message was followed by "WTF" and a link. "Clicking on the WTF link would take you to a webpage which contained some trivial code which used a CSRF -- cross-site request forgery -- technique to automatically post from the visitor's Twitter account," he said.
Twitter users, however, would be none the wiser that they'd just stumbled into a CSRF attack, since after clicking the link all they saw was a blank screen. Meanwhile, the attack had already used the user's Twitter account to post more goat-related messages with malicious links.
"Some high-profile Twitter users, including Robert Scoble, fell foul of the attack," said Cluley. "Of course, having such popular Twitter users affected accelerated the spread of the message."
This attack follows a recent and arguably more dangerous attack that used a cross-site scripting vulnerability to craft a malicious link. All a user had to do was to move his or her mouse pointer over the link, and the malicious code could open pop-up windows or third-party websites.
For the goat-related attack, by late Sunday, Twitter said that it had "fixed the exploit" by disabling the links and was "in the process of removing the offending Tweets."
But Cluley said the underlying CSRF holes are "an obvious security problem in Twitter which must be addressed as a matter of urgency -- otherwise we can expect further, perhaps more dangerous, attacks."