Chinese state-linked hackers target Asian telecom operators

Researchers have discovered that various threat actors groups associated with Chinese state-linked espionage have been conducting a sustained hacking campaign targeting telecommunications operators in an unnamed Asian country since at least 2021.

The attackers relied on custom malware and tactics tied to several China-linked espionage groups, suggesting Chinese state sponsorship.

Malware Variants Used in Chinese Espionage Campaign
Researchers from Symantec observed the use of several custom malware linked to China-based threat actors, including:

• Coolclient: A backdoor used by the Fireant group that logs keystrokes and communicates with command servers. The campaign utilized a version delivered via a trojanized VLC media player. It is linked to the Fireant group, also known as Mustang Panda or Earth Preta.
• Quickheal: A backdoor associated with the Needleminer group, also known as RedFoxtrot or Nomad Panda. The variant used in the campaign was nearly identical to those documented in 2021. It communicated with a command server at swiftandfast[.]net.
• Rainyday: A backdoor tied to the Firefly group, also known as Naikon. Multiple variants were deployed using trojanized executables to sideload malicious loaders and decrypt payloads. At least one loader variant matched those linked to Firefly in 2021.

The attackers also used a variety of tactics, techniques, and procedures (TTPs) to compromise targets. These included keylogging malware that were possibly custom-developed, and port scanning tools to identify vulnerable systems. They also employed credential theft through the dumping of registry hives and exploited the Remote Desktop Protocol (RDP).

Additionally, they used a publicly available tool, Responder, to act as a Link-Local Multicast Name Resolution (LLMNR), NetBIOS Name Service (NBT-NS) and multicast DNS (mDNS) poisoner. Nearly all victims in the campaign were telecoms operators, along with a services company that caters to the telecoms sector and a university in a different country in Asia.

Campaign Motives and Attribution
The custom malware exclusively used by Fireant, Needleminer and Firefly provides strong evidence that this campaign involves Chinese state-sponsored groups. Firefly has been linked to a Chinese military intelligence unit by the U.S.-China Commission. The level of coordination between the groups involved is unclear but possibilities include independent action, personnel/tool sharing, or active collaboration.

The ultimate motives behind the hacking campaign remain uncertain. Potential objectives include intelligence gathering on the telecommunications sector, eavesdropping on voice and data communications, or developing disruptive capabilities against critical infrastructure.

To protect against these threats, telecom operators and other organizations should ensure they have the latest protection updates and implement robust security measures to detect and block malicious files. The researchers shared several Indicators of compromise and file hashes to help defenders detect against the campaign. The Cyber Express