The Washington Post reports that News Corp's (NYSE: NWS) Fox News was among the news agencies that downloaded an al-Qaeda video that was leaked by the U.S. government, and in so doing unveiled a security hole in al-Qaeda's network that permanently damages a valuable source of information about its plans.

According to the article, many news agencies downloaded transcripts of the video, but Fox News cited the source, effectively closing that avenue of information for good.

A little background is in order here. Search for International Terrorist Entities (SITE) was established in 2002 to track and expose terrorist groups. According to the Post piece, SITE obtained a new Osama bin Laden video ahead of its official release last month, and around 10 a.m. on September 7, it notified the Bush administration, giving two senior U.S. officials access on the condition that they not reveal what they had until al-Qaeda had officially released the broadcast. But by mid-afternoon that day, the video and a transcript of its audio track had been leaked from within the Bush administration to media outlets. Fox News had the transcripts up and sourced to SITE by 3 p.m.