Brute Ratel C4 (BRC4), also known as BOLDBADGER and BruteRatel, has been making waves in the cybersecurity industry since its debut in December 2020. This commercial framework is designed for red-teaming and adversarial attack simulation, offering sophisticated evasion techniques to bypass modern endpoint detection and response (EDR) systems and antivirus (AV) software. Both ethical hackers and malicious actors find this tool invaluable due to its capabilities.
The Brute Ratel C4 primarily targets individuals, utilizing the Badger backdoor agent for deployment and communication with its command-and-control (C2) server. The agent communicates through various channels such as DNS over HTTPS, HTTP, HTTPS, SMB, and TCP, making detection challenging for security solutions. Additionally, data exchanged between the agent and the C2 server is encrypted using custom protocols, further obscuring malicious activities from network monitoring tools.
The Badger agent’s versatility allows attackers to execute arbitrary commands, enabling them to manipulate the target environment as needed. This includes running shell commands, transferring files, and executing files for further exploitation, crucial for lateral movement within a network. The ability to pivot from one system to another and maintain persistence is vital for attackers.
Brute Ratel C4 includes a suite of commands for credential harvesting, reconnaissance activities like port scanning, and keystroke logging. These capabilities provide attackers with the necessary tools for infiltration, data exfiltration, and privilege escalation within a network. The framework’s focus on evasion, with custom encryption for data transmission and operations executed in memory, helps attackers avoid detection by security solutions.
The distribution of cracked versions of BRC4 in the cybercriminal underground has increased its accessibility among less sophisticated threat actors since September 2022. This democratization of advanced attack methodologies poses a significant risk by flooding the threat landscape with diverse malware variants designed to evade detection and exploit vulnerabilities.
In conclusion, Brute Ratel C4 represents a significant advancement in malware technology, combining advanced evasion techniques with powerful command execution capabilities. Understanding tools like BRC4 is crucial for organizations to develop effective cybersecurity defenses against evolving threats. Continuous monitoring, employee training, and robust incident response strategies are essential for countering the sophisticated tactics employed by such malware and reducing their impact on organizational security.