Cyber Defense

Report: US hack of North Korea provided proof in Sony attack

The United States reportedly knew that North Korea was behind last fall’s high-profile Sony hack because the National Security Agency was already inside North Korea’s networks, something that would provide another example of the Defense Department’s willingness to engage in offensive, or at least proactive, cyber operations.

The NSA in 2010 started breaking into the Chinese networks that provide North Korea with Internet access, found its way into North Korean systems and planted malware to track the operations of North Korea’s growing hacking force, including the Bureau 121 unit blamed for the Sony attack, according to a report in the New York Times.

The operation was part of a decade-long effort to crack into the networks of foreign adversaries and implant software that would form a kind of “early warning radar” against hacking attempts. And although in the case of the Sony hack it didn’t alert intelligence analysts to the hack as it was happening (phishing emails that enabled the intrusion slipped through), it did allow analysts after the fact to quickly attribute the attack to North Korea, the Times reported.

The attack on Sony, which had been brewing for months, broke Nov. 24, when hackers release internal emails, salary information and other private data, and threatened retaliation if the Sony movie “The Interview”—a farcical comedy depicting an assassination attempt against North Korean leader Kim Jong Un—was released to theaters. U.S. officials and then President Obama blamed North Korean within a matter of weeks, which was notable both for the speed with which they made the claim and because it was the first time the U.S. had named a foreign government as the source of a specific attack. (Though the Justice Department did charge five Chinese military officials last year with cyber espionage for alleged attacks on six U.S. companies.)

Although private-sector security experts expressed doubt that North Korea was behind the attacks, U.S. officials held firm, and eventually followed up with sanctions against individuals in North Korea. In late December, North Korea also was hit with widespread Internet outages, which it blamed on the United States.

The episode illustrates the growing importance of the cyber domain and DOD’s preparation for offensive operations, something the Joint Chiefs, for the first time, expressed openly in its most recent document on cyberspace operations. That document, issued in February 2014 and made public in October, defines offensive cyber operations as those "intended to project power by the application of force in and through cyberspace," but planting malware on foreign networks to create an early warning system and identify the source of attacks would seem to be a logical part of the program.

After all, in the event of cyber war (Obama referred to the Sony hack as “cyber vandalism”), any retaliation would hinge on knowing where an attack came from. Attribution—identifying the actual source of an attack—is the one of the hard parts of cybersecurity, because of hackers’ ability to route attacks through servers around the world. One reason private security experts doubted North Korea’s role in the Sony hack was the ease with which an outside group could make it look like it came from North Korea. Having malware already in place that could locate the source of an attack—ideally, before it does damage—would make attribution a lot easier.

About the Author

Kevin McCaney is a former editor of Defense Systems and GCN.

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