ChamelDoH: A New Linux Malware That Uses DNS-Over-HTTPS for Remote Access

As cyber threats continue to evolve, so do the methods and techniques utilized by malicious actors. One of the latest threats discovered is a new Linux malware known as ChamelDoH. This malware has been linked to the notorious ChamelGang and employs DNS-over-HTTPS (DoH) for communication with its command-and-control (C2) infrastructure. In this article, we will explore the unique features of ChamelDoH and its impact on enterprise security.

Description of the Malware

ChamelDoH is a large C++ binary that is primarily designed for remote access to a system. Upon execution, it immediately begins to collect reconnaissance data using various system calls and compiles it into a JSON object. This information is then transmitted to the C2 infrastructure using DoH tunneling.

The use of DoH tunneling is a unique aspect of ChamelDoH. This technique allows the malware to bypass traditional security measures such as firewalls and network monitoring tools that do not inspect encrypted traffic. The encrypted data is transformed into base64 format and inserted as a subdomain. This technique resembles C2 communication through domain fronting, which is often used by advanced persistent threats (APTs) to maintain persistence and evade detection.

Unique Approach to C2 Techniques

ChamelDoH distinguishes itself through its original approach to Command and Control (C2) techniques. The malware uses AES128 encryption to secure its communication, thereby ensuring confidentiality and preventing detection by traditional security methods. This approach makes detection and analysis of the malware challenging, increasing the difficulty of identifying the source of the infection and determining the level of data compromised.

Tasks performed by the implant

Once the implant is established on a system, it can perform several types of tasks, including executing commands, downloading files, and changing working directories. This allows the attacker to maintain persistent access to the system and move laterally through the network, bypassing traditional security barriers and accessing sensitive information.

Ongoing analysis by the Stairwell Threat Research Team

As ChamelDoH is a new piece of malware, ongoing analysis is being conducted by the Stairwell Threat Research team to examine its capabilities and other tools utilized by ChamelGang. The team is working to develop detection and prevention strategies to mitigate the impact of the malware on organizations.

ChamelDoH is a new Linux malware that underscores the continued evolution of cyber threats and the need for organizations to remain vigilant in their security posture. The use of DoH tunneling and encryption techniques highlights the sophistication of the malware and the need for advanced detection strategies. Organizations should ensure that their security measures are equipped to detect and mitigate these types of threats, including the latest detection software, regular security training, and the adoption of best practices for security posture. Only through proactive efforts such as these can organizations protect themselves against the ever-evolving threat landscape.

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