The cyber operation was undertaken by MI6 and and Britain's Government Communications Headquarters to disrupt efforts by al-Qaida in the Arabian Peninsula to recruit so-called lone wolf terrorists with the English-language Inspire magazine, The Daily Telegraph said.
The British publication did not indicate when the cyberattack on Inspire occurred. British and U.S intelligence had planned separate operations after learning the magazine was about to launch in June 2010, developing a number of cyber countermeasures, including computer viruses.
When visitors tried to download the Webazine, instead of getting instruction about how to "Make a Bomb in the Kitchen of Your Mom" by "The AQ Chef," they got garbled computer code that was a Web page of recipes for "The Best Cupcakes in America."
Among other things, the substituted text produced by Main Street Cupcakes in Hudson, Ohio, included recipes for a mojito cupcake and a rocky road cupcake, the Telegraph said.
The text was supposed to be a recipe for making a lethal pipe bomb with household items, intelligence officers said.
The cyberattack also deleted an article called, "What to Expect in Jihad," by now-deceased al-Qaida leader Osama bin Laden, and his deputy, Ayman al-Zawahiri, the Telegraph said.
Inspire is produced by the radical preacher Anwar al-Awlaki, a leader of al-Qaida in the Arabian Peninsula who lived in Britain and the United States, and an associate.