Hackers frequently exploit DNS and ICMP tunneling to covertly transmit data and bypass network security measures. These protocols, often left vulnerable by inadequately protected firewalls, can be manipulated to create hidden communication routes, allowing the transfer of sensitive data and unauthorized access. This technique enables threat actors to maintain persistence within compromised networks while avoiding detection.
Positive Technologies researchers recently discovered that ExCobalt’s new tool, GoRed, employs DNS and ICMP tunneling for communication with its Command and Control (C2) servers. ExCobalt, likely an extension of the notorious Cobalt group known for targeting financial institutions, uses GoRed as a backdoor to execute commands, harvest credentials, and exfiltrate data. The PT ESC CSIRT team identified GoRed during an incident response in March 2024.
GoRed’s key features include a C2 framework, RPC protocol for C2 communication, and various tunneling methods such as DNS, ICMP, WSS, and QUIC. It also possesses capabilities for reconnaissance, data collection, serialization, encryption, and exfiltration to dedicated servers. Multiple variants of this backdoor have been encountered, often found alongside other tools like Mimikatz and Metasploit, indicating its widespread use in cyber espionage activities.
ExCobalt continues to enhance GoRed with new features to improve data collection and maintain secrecy. The group’s ability to leverage vulnerabilities and create sophisticated tools poses a significant threat to affected organizations. Consequently, robust security measures and continuous monitoring are essential to detect and mitigate such advanced evasion techniques.
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