In September, it was revealed that Iranian hackers had managed to infiltrate a Navy network, but apparently the attack was far more extensive than initially reported. The Wall Street Journal writes that it took approximately four months for the Navy to finally purge the intruder from its largest unclassified computer network, even though Navy officials claimed in September that the threat had been removed. It took so long, in part, because “The thing got into the bloodstream, and it wasn’t just in the main arteries; it was in all the little capillaries,” a senior U.S. official said. In 2012, the U.S. concluded that Iran lacked the capacity for cyberoffensives, but the Islamic Republic increasingly has been increasingly using this mode of attack, including a series of “denial-of-service” strikes on U.S. banking websites. However, September's offensive was far more elaborate than those.