Twitter filters malicious URLs

UPDATED: Twitter, long under siege by malware that propagates through its popular system, is now filtering malicious URLs, according to a blog post by F-Secure chief research offer Mikko Hypponen.

“Twitter hasn’t announced this, but we just noticed that they have now started filtering Tweets that contain links to known malware sites,” he wrote. He added that a source claims that the company is employing a Google API to find bad URLs.

According to Hypponen, when a user tries to post a bad URL, Twitter instead posts a message, “Oops! Your tweet contained a link to a known malware site!”

Twitter had not replied to inquiries by our press time.

While some commentators have criticized the filtering system for not being flawless, the company should be praised for protecting its users. One security expert recently said that security measures that provide partial protection are worthwhile.

The protection does not cover URLs made shorter by services like, Hypponen said in an e-mail to

There’s a clear need for the security measure, as some of Twitter’s most famous users have been hacked.

Update adds comment by Hypponen to

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