When Legitimate RMM Tools Become an Attack Vector

Remote Monitoring and Management (RMM) tools are widely used by IT teams to support remote administration and system maintenance. Tools such as AnyDesk, TeamViewer, and ScreenConnect provide powerful capabilities for managing endpoints across distributed environments.

However, these same capabilities have made RMM tools increasingly attractive to attackers.

In many modern intrusions, threat actors deploy legitimate remote access tools after gaining an initial foothold. Because these applications are commonly used by IT teams, their activity can blend into normal administrative behavior.

From a monitoring perspective, this creates a difficult challenge: the tool itself is legitimate — the usage is not.

The Problem: Blending Malicious Activity into Normal IT Operations

Once installed, RMM software allows remote operators to:

• Access desktops and servers

• Transfer files

• Execute commands remotely

• Maintain persistent remote access
  

Attackers exploit this functionality to establish control without introducing traditional malware.

Because the traffic and processes associated with these tools appear legitimate, they can evade many traditional detection methods.

From Threat to Detection

Based on this activity, we implemented a detection rule designed to surface the execution of common RMM tools such as AnyDesk, TeamViewer, and Atera when launched outside standard installation paths.

The detection leverages process creation events (Event ID 4688) and focuses on identifying these binaries when executed from user-writable or otherwise unusual directories — a common pattern in unauthorized deployments.

You can find the full detection logic here.

Security Implications

Unauthorized RMM tools can provide attackers with:

• Persistent remote access

• Lateral movement capabilities

• Administrative control over systems
  

When left undetected, they allow attackers to operate in a way that closely resembles legitimate IT activity.

Key Takeaway

Attackers don’t need custom malware when they can use legitimate tools already trusted in the environment.

That’s why visibility into how remote access tools are introduced and used is critical — allowing us to identify unauthorized activity early, even when it looks like normal administration. -Written by Stanislav Stoychev, Security Analyst, CyberSift