SystemBC C2 Analysis: 1,570 Victims of The Gentlemen Ransomware

A recent investigation into the command-and-control (C2) infrastructure of the SystemBC botnet has revealed a significantly larger impact than previously estimated. According to The Hacker News, analysis by researchers at Check Point has identified more than 1,570 victims globally associated with a single C2 server. This activity is tied to a Ransomware-as-a-Service (RaaS) entity known as “The Gentlemen,” which utilizes the SystemBC proxy malware to facilitate long-term access and data exfiltration.

Technical Analysis of SystemBC Botnets

SystemBC is a persistent threat, frequently functioning as a SOCKS5 network proxy that enables attackers to tunnel malicious traffic through infected hosts. This capability allows threat actors to bypass firewall restrictions and mask the origin of their traffic, making it an ideal tool for maintaining a foothold within a target environment. Unlike standard remote access trojans that focus on direct host control, SystemBC acts as a bridge, allowing for seamless Lateral Movement and remote management of internal assets.

Technically, SystemBC is often written in C++ and maintains a small footprint to avoid detection by traditional antivirus solutions. It typically establishes persistence through the creation of scheduled tasks or registry modifications. Once active, the malware communicates with its C2 infrastructure using a custom binary protocol over TCP. The Gentlemen ransomware operation leverages these capabilities to bridge the gap between initial access and final encryption. By proxying TTP stages through SystemBC, the attackers can deploy secondary payloads, such as Cobalt Strike or the ransomware itself, while keeping their primary infrastructure hidden from SOC analysts.

The Role of The Gentlemen Ransomware Operation

The Gentlemen RaaS has emerged as a professionalized threat actor group, focusing on affiliate-driven distribution. This group frequently provides affiliates with pre-configured tools, including SystemBC, to streamline the compromise of corporate networks. While initial entry often involves Phishing campaigns or the exploitation of a known CVE, the deployment of SystemBC ensures that even if the initial entry vector is closed, the attackers retain a viable backchannel into the network.

In many cases, the malware is deployed following a successful Privilege Escalation on a workstation or server. The 1,570 victims identified in the recent C2 server analysis span various geographic regions and industry sectors, suggesting that The Gentlemen do not target a specific vertical but rather seek any high-value target with exploitable weaknesses. The use of SystemBC is a strategic choice, as it maps directly to several techniques within the MITRE ATT&CK framework, specifically under Command and Control (T1090 - Proxy) and Persistence (T1053 - Scheduled Task/Job).

Strategies to detect SystemBC proxy malware

To effectively defend against this threat, security professionals must focus on identifying SystemBC C2 server indicators within their network telemetry. Because the malware relies on SOCKS5 tunneling, monitoring for unusual outbound connections on non-standard ports (e.g., ports 4000-5000 or 8000-9000) is a primary detection method. Furthermore, implementing an EDR solution that flags the creation of unexpected scheduled tasks with obfuscated arguments can stop the malware before it establishes long-term persistence.

Detection logic should also be integrated into the SIEM to correlate network proxy traffic with suspicious process execution, such as PowerShell or CMD spawns from uncommon parent processes. Organizations should prioritize auditing their egress traffic and applying strict firewall rules that prevent unauthorized devices from initiating external SOCKS5 sessions. As The Gentlemen continue to evolve their delivery methods, proactive hunting for these proxy-related indicators remains the most effective way to prevent a full-scale ransomware deployment.