Legal sources tell NBC News that the former second-highest-ranking officer in the U.S. military is now the target of a Justice Department investigation into an alleged leak of classified information about a covert U.S. cyberattack on Iran’s nuclear program. According to legal sources, retired Marine Gen. James “Hoss” Cartwright, the former vice chairman of the Joint Chiefs of Staff, has been notified that he’s under investigation for allegedly leaking information about a massive attack using a computer virus named Stuxnet on Iran’s nuclear facilities. Gen. Cartwright, 63, becomes the latest alleged leaker targeted by the Obama administration, which has already...