Twitter plugged a security vulnerability in its popular TweetDeck application Wednesday, after disabling the system for over an hour earlier in the day to fix it. People logged into the service during the breach got odd pop-up messages. Their systems also randomly re-tweeted messages containing potentially malicious computer code scripts. When the site was taken down, TweetDeck tweeted, “We’ve temporarily taken TweetDeck services down to assess today’s earlier security issue. We’ll update when services are back up.”