NEW YORK (1010 WINS/WCBS 880/AP) —  A new way to cause mischief quickly spread through short-messaging service Twitter Tuesday morning before the site could fix the problem, as mysterious “tweets” of blocked-out text propagated themselves and caused popup windows to open.

Shortly before 10 a.m., Twitter said on its “safety” feed on the site that the attack has been “fully patched” and no longer works.

The hack had been extra nefarious because the tweets activated without being clicked on – it was enough for Web surfers to move their mouse cursors over them. But it only affected visitors to

Various third-party programs used to send and read tweets were unaffected. Larry Magid, CBS News and CNET technology consultant, said it was safe to use applications such as TweetDeck or Twitterific. The popups could contain malicious code that could take over poorly protected computers.

“”It sounds like something that’s been around for a long time but it’s the first time we’ve seen it on Twitter,” Huffington Post’s Social Media Editory, Rob Fishman told 1010 WINS. “Which does make you wonder, just because Twitter’s become such an influential platform, especially for the news industry.”

Security breaches had been common in Twitter’s early days, but the company has since worked to beef up its security and the problems have become less common.

(Copyright 2010 by The Associated Press. All Rights Reserved.)

Watch & Listen LIVE