Korean APT Adds Rare Bluetooth Device-Harvester Tool

ScarCruft, an advanced persistent threat group known for attacking organizations with links to the Korean peninsula, has become more dangerous.

An analysis of recent data associated with the group shows that it has acquired new tools and is testing new exploits in preparation for future campaigns, Kaspersky Lab said Monday.

Telemetry associated with ScarCruft shows that the threat actor has also developed an interest in attacking mobile devices and has increasingly begun adapting legitimate tools and services in its espionage campaigns.

One of the new tools that ScarCruft has developed is a rare Bluetooth device-harvester designed to collect the names and addresses of Bluetooth devices, device type, whether it is connected, and whether it requires authentication. The malware leverages the Windows Bluetooth API to fingerprint Bluetooth devices, Kaspersky Lab said.

Victims of the ongoing campaign include investment firms and trading companies in Russia and Vietnam that appear to have links to the North Korean government. Entities in North Korea and Hong Kong also have been targeted in its latest campaign.

"ScarCruft has shown itself to be a highly-skilled and active group," Kaspersky Lab said in a report. "Based on ScarCruft's recent activities, we strongly believe that this group is likely to continue to evolve."

Security researchers consider ScarCruft—also known as Reaper and Group 123—to be one of the most active APT groups in the Asian region. It is a Korean-language speaking group that is likely state-sponsored and focused on collecting information pertaining to North Korea and on businesses with connections to the reclusive country.

The group also has been targeting diplomatic missions around the world according to Kaspersky Lab. ScarCruft's victims have included organizations in China, India, South Korea, Kuwait, and Nepal.

ScarCruft attracted some attention early last year for employing an Adobe Flash zero-day exploit in an attack campaign dubbed Operation Daybreak that targeted more than two-dozen high-profile organizations. At the time, Kaspersky Lab researchers believed the threat group had purchased the exploit in the dark market using cryptocurrency, rather than developing the exploit on its own. The researchers assessed then that the group did not have the ability to develop a zero-day exploit.

Continued Evolution

But ScarCruft has ramped up its activities over the past year and has developed into a resourceful and skilled adversary, according to Kaspersky. Like most other threat groups these days, ScarCruft's typical attack strategy is to gain an initial foothold at a targeted organization using spear-phishing emails or watering-hole attacks. During the initial infection stage, ScarCruft downloads a dropper capable of bypassing Windows User Account Control on the compromised system.

The dropper then executes the next payload, which takes advantage of code that organizations normally use for penetration testing in order to escalate privileges. "In order to evade detection at the network level, the malware uses steganography, hiding the malicious code in an image file," Kaspersky Lab said in its report.

ScarCruft also installs ROKRAT, a backdoor that is designed to harvest information from computers and devices on the compromised network and to send the stolen data to either Box, Dropbox, Yandex.Disk, and pCloud.

At least one of ScarCruft's recent victims was an organization that another Korean-speaking threat group called DarkHotel had already previously compromised. Campaigns of the two groups have overlapped previously as well, suggesting that both groups are interested in the same targets despite having very different tools, techniques, and procedures.

"This leads us to believe that one group regularly lurks in the shadow of the other," the Kaspersky Lab report said.

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