FireEye Drops After Cybersecurity Company Says It Was Hacked (1)

FireEye Inc., a prominent U.S. cybersecurity company, acknowledged that it had been breached, probably by hackers from a foreign adversary. The attackers made off with sensitive tools that FireEye uses to find vulnerabilities in clients’ computer networks.

The attackers were a “nation with top-tier offensive capabilities,” said Chief Executive Officer Kevin Mandia. He didn’t identify the country suspected in the attack, but a person familiar with the incident said investigators believe hackers closely aligned with the Russian government were behind it.

The hackers “tailored their world-class capabilities specifically to target and attack FireEye,” Mandia said in a company ...