U.S. cybersecurity firm FireEye discloses breach, theft of hacking tools

FILE PHOTO: The FireEye logo is seen outside the company's offices in Milpitas, California, December 29, 2014. REUTERS/Beck Diefenbach

(Reuters) -FireEye, one of the largest cybersecurity companies in the United States, said on Tuesday that it has been hacked, likely by a government, leading to the theft of an arsenal of internal hacking tools typically reserved to privately test the cyber defenses of its clients.

The hack of FireEye, a company with an array of business contracts across the national security space both in the United States and its allies, is among the most significant breaches in recent memory. The company's shares dropped 8% in after-hours trading.