The erroneous tweets appeared just after 02:00 Eastern Time in the U.S. and remained up more than six hours later, without any correction from Fox News. The lapse raised questions about whether Fox had lost control of the Twitter account, or was merely caught napping on Federal holiday. By noon Eastern Time, Fox News had removed the tweets and posted its own story covering the incident. The source of the compromise is not known. Twitter account takeovers of celebrities like Ashton Kutcher have been common many stemming from insecure HTTP sessions that were sniffed.
Source: https://threatpost.com/fox-news-caught-sleeping-after-twitter-account-hacked-070411/75392/