Agent-based or Agentless Security? This has been a longstanding debate among IT professionals. It is a hot topic that has gained more prominence in the cybersecurity community following the well-publicized CrowdStrike incident that disrupted computers globally. But what exactly is an agent, and how can security be managed without one? Before delving into the specifics of agents, let’s use an analogy to better understand the dilemma.  

Security Guards vs. Security Cameras 

Imagine you are appointed as the head of security for a new manufacturing facility. It’s your responsibility to decide on the security approach. A longstanding traditional method has been employing security guards. The advantage of having security guards is their direct access to every part of the building. Each guard can work together in a coordinated effort or act independently if they notice something suspicious in their immediate area. They can respond quickly to an incident and can continue to operate in a variety of conditions. However, guards cannot be everywhere at once, and not all of them operate with the same effectiveness. Beyond their salaries and benefits, you must also manage additional costs such as employee turnover and maintaining a breakroom. 

Another option is to install cameras throughout the facility. This provides a holistic view of the entire facility for centrally located staff that do not have to leave their station. You can purchase and maintain a lot of cameras for the price of a single security guard and each camera works equally well right out of the box with little need for maintenance. Of course, the cameras only work as dependably as the infrastructure that supports them. If the power goes out or a network switch fails, security is immediately compromised.  

Agent vs Agentless 

Agent-based products require a specialized software component to be installed on each monitored system. That component is the agent, and because it operates on the very system that it is monitoring, it can provide customized in-depth scanning and monitoring in real time. Although managed by a centralized application, agents can function independently, making them suitable for remote locations with minimal connectivity. Examples include Windows Defender for Endpoint and Mobile Device Management solutions. 

In contrast, agentless tools do not reside on the monitored hosts. These tools collect information using non-invasive methods such as cloud APIs, snapshot collection or log file analysis. All this collected information is then analyzed to build an inventory and assess the discovered security risks throughout the environment. Think of the camera system mentioned earlier as an agentless security solution that examines everything from a distance. Prisma Cloud by Palo Alto Networks or any Security Information and Event Management (SIEM) solution are examples of an agentless security solution.  

Deployment and Maintenance 

While agents can operate independently when necessary, they require assistance with deployment. Although most agent rollouts can be automated today, the deployment process still needs to be monitored. An agent must be deployed each time a new device is onboarded, or a system is wiped. Agents also need to be correctly configured and updated periodically. Some systems, such as certain cloud environments, cannot accommodate agents, which is a limitation since a device cannot be monitored without an agent. 

A major advantage of agentless solutions is that deployment is typically a one-time setup. This approach significantly reduces deployment time and allows agentless security tools to monitor nearly every device within an environment. Agentless solutions are particularly well-suited for complex, large-scale enterprises where resources are constantly being spun up. However, these solutions rely on connectivity, and losing connectivity means losing security. They are highly dependent on their supportive infrastructure and compatibility issues can occur within hybrid network environments.  

Performance and Resource Utilization 

Any security agent will require some local resources, which can potentially degrade the performance of its host system. In contrast, agentless security solutions are designed to be lightweight and do not compete for local resources to the same extent as agent-based solutions. However, it is important to note that agentless security still requires a robust and reliable infrastructure to function effectively. 

Issues of Scalability 

Scalability is an issue for large complex enterprises when it comes to agent-based solutions due to the required agent deployment for every device. Agentless solutions are usually more scalable, especially for expansive enterprises comprised of multiple sites and clouds.  

The Best of Both Worlds: Integrating Agent and Agentless Solutions 

Think back to our analogy of security guards and cameras. It doesn’t have to be an either-or situation. Cameras provide highly scalable visibility, but they cannot intervene during an incident. On the other hand, security guards can intercept intruders but are limited to what they can see. However, when cameras are used to supplement the capabilities of security guards, your overall security is significantly enhanced. 

Agent-based security acts as the “boots on the ground” for your organization. These agents can collect detailed, granular information from their host devices, surpassing the capabilities of any agentless solution. They can also automate and enforce security policies directly on their devices without needing a constant connection to a central server. However, like security guards, agents cannot be everywhere at once and require a level of maintenance and support that agentless solutions do not.  In contrast, agentless solutions are highly scalable and rarely require human assistance or maintenance. They offer visibility into all areas of your environment and operate 24/7. 

This is why integrating both agent-based and agentless security solutions is essential for securing your business. To put it simply, their combined effectiveness is greater than the sum of their individual capabilities. With both solution types working in cohesion with one another, you now have an agent-based solution that can continuously monitor and remediate its hosts even if the internet is down. At the same time, an agentless solution, such as an MDR based on a Security Data Lake, can provide ongoing monitoring and threat protection. It can help identify and respond to threats that agent-based systems might miss or be unable to address promptly. Agentless solutions can bridge the gaps left by agents. They can offer your security team a comprehensive, real-time view of your security landscape by drawing information from multiple diverse sources. Together, they can create the multilayer security strategy you need to ensure continuity for your business.