Abuse of Legitimate Remote Access Tools for Lateral Movement and Persistence

Threat actors are increasingly leveraging legitimate remote access tools, such as PuTTY and various remote monitoring and management (RMM) platforms, to facilitate lateral movement, data exfiltration, and persistent access within compromised networks. Attackers exploit the "living off the land" nature of these tools, blending their malicious activities with normal administrative operations to evade detection. In the case of PuTTY, adversaries use binaries like plink.exe and pscp.exe to move laterally and exfiltrate sensitive data, often leaving behind subtle forensic traces such as SSH host keys in the Windows registry. These artifacts can be crucial for investigators to reconstruct attacker activity, even after extensive log and artifact cleanup by the attackers.

Similarly, security researchers have observed a surge in incidents where multiple RMM tools are abused in attack chains. Threat actors compromise or install RMM platforms like ScreenConnect, TeamViewer, Atera, NinjaRMM, and GoTo Resolve to maintain long-term access and persistence. Attackers often use phishing lures to trick victims into installing rogue RMM software, and may deploy several RMM tools in succession to ensure continued access even if one is detected and removed. These tactics highlight the ongoing challenge for defenders in distinguishing between legitimate and malicious use of remote access utilities, underscoring the need for robust monitoring and baselining of such tools within enterprise environments.