An advanced persistent threat (APT) actor group known by several different names such as Tick, Redbaldknight and Bronze Butler carried out a number of cyber attacks targeting East Asia.

The APT group used custom tools and compromised websites for C2 servers, the hacker group primarily targets South Korea and Japan.

Security researchers from Cisco Talos observed the APT group recurring patterns in the actor’s use of infrastructure, from overlaps in hijacked command and control (C2) domains to differing campaign C2s resolving to the same IP.

Datper Malware

With the recent campaign, the hacker group uses Datper malware written in Delphi, capable of executing shell commands on the victim machine to retrieve hostnames and drive information.

The attackers used compromised Korean laundry service website for C2 communication, once the malware is dropped it gathers victim machine, including system information and keyboard layout.

At the time of our investigation the C2 servers are not active, so no other details available, “it is possible the malware samples are being delivered using web-based attacks, such as drive-by downloads or watering hole attacks,” researchers said.

“We confirmed that the actor periodically changed their C2 infrastructure and appears to have a history of identifying and penetrating vulnerable websites located in these countries.”

The same infrastructure found shared between the malware families Datper, xxmm backdoor, and Emdivi. Also, researchers found that the same IP used by Datper and Emdivi malware families.

With the previous campaign the hacker group uses Daserf Backdoor with stealthy techniques to evade detection and its use steganography, embedding codes are using to hide the malicious code with a spreading medium such as images.