A recent report from LevelBlue Labs highlights a new tool called SbaProxy, which is being used by threat actors to hijack legitimate anti-virus software and create proxy connections through a command and control (C&C) server. SbaProxy is distributed in multiple formats, including DLLs, EXEs, and PowerShell scripts, all carrying the same malicious functionality. The tool is designed to appear as legitimate anti-virus components, making it difficult to detect and bypass security checks. The attackers modify the original anti-virus binaries and sign them with counterfeit certificates, allowing the malicious software to evade detection by masquerading as benign components.
SbaProxy works by establishing a proxy service between the infected machine and a C&C server, which can then be used for malicious activities, potentially including facilitating further attacks. The tool is designed to be stealthy, with its components being signed with valid or seemingly valid certificates, some of which are still valid at the time of the report. The attackers are using this tool to generate revenue by selling proxy services to other criminals. The functionality of SbaProxy is robust and allows for the forwarding of data between the target and the C&C server, effectively routing traffic through the infected system.
The tool is distributed in various formats, but the core functionality remains consistent across these different variants. When distributed as DLLs or EXEs, SbaProxy masquerades as anti-virus components but includes malicious code designed to establish a proxy connection. For PowerShell scripts, the code is unmodified, retaining the original function names and being relatively straightforward and easy to read. While the tool itself doesn’t feature persistence, its secondary components allow for the infection to remain active in memory, making it harder to detect and remove. The lack of persistence in some formats is a tactic to minimize detection and maintain a low profile on the infected system.
LevelBlue Labs has been actively tracking this threat actor and is committed to continuing to monitor the evolution of the tools used in these attacks. SbaProxy represents a concerning shift in cybercriminal tactics, as it leverages trusted software to avoid detection and enable malicious activities. The use of counterfeit certificates and the modification of legitimate binaries demonstrates the increasing sophistication of threat actors. As cybercriminals continue to innovate and evolve, organizations must remain vigilant and proactive in their defense strategies to stay ahead of these emerging threats.
Reference:
