Darkhotel Deploys Zero-Day From Hacking Team

The Darkhotel cyberespionage crew keeps adding to its bag of tricks: New evidence today from Kaspersky Lab shows that the group seems to have latched on to some of the zero-day vulnerabilities exposed by the Hacking Team data dump last month.

Known best for breaking into Wi-Fi networks in luxury hotels to target very high-profile corporate and government executives, the team has long depended on zero-day and half-day vulnerabilities to strike its targets. According to Kaspersky, Darkhotel has gone through half a dozen or more zero-days targeting Adobe Flash Player in the past year, investing considerable funds to beef up a quiver meant to hit the proverbial bullseyes. But it isn't above striking when opportunities like the breach of Hacking Team present themselves.

“Darkhotel has returned with yet another Adobe Flash Player exploit hosted on a compromised website, and this time it appears to have been driven by the Hacking Team leak," says Kurt Baumgartner, principal security researcher at Kaspersky Lab. "The group has previously delivered a different Flash exploit on the same website, which we reported as a zero-day to Adobe in January 2014. Darkhotel seems to have burned through a pile of Flash zero-day and half-day exploits over the past few years, and it may have stockpiled more to perform precise attacks on high-level individuals globally."

The Korean group initially focused 90 percent of its efforts targeting victim organizations in Japan, Taiwan, China, Russia, and Hong Kong. But over the past year it has expanded its geographical reach to North Korea and South Korea, Russia, Bangladesh, Thailand, India, Mozambique, and Germany.

According to Baumgartner and his team, Darkhotel depends on dogged persistence on the social engineering front.

"The Darkhotel APT will relentlessly spearphish specific targets in order to successfully compromise systems," Baumgartner says. "Some targets are spearphished repeatedly with much the same social-engineering schemes."

For example, if a Darkhotel spearphisher is sending out a fake schedule file with malicious payloads, he'll send one in February with a naming convention that uses the current date,and then send another one in May with the same naming convention and a new one to match the date.

Additionally, the group has leaned on stolen certificates on an ongoing basis. Kaspersky says it believes the crew maintains a stockpile of these stolen certs in order to use them in their downloaders and backdoors to evade detection.

"Darkhotel now tends to hide its code behind layers of encryption. It is likely that it has slowly adapted to attacking better-defended environments and prefers not to burn these stolen digital certificates. In previous attacks it would simply have taken advantage of a long list of weakly implemented, broken certificates," Baumgartner says. "Not only are its obfuscation techniques becoming stronger, but its anti-detection technology list is growing. "