Network Detection and Response (NDR): why is network visibility critical to security?

Today’s cyber security strategy is largely focused on endpoint protection. We deploy sophisticated EDR (Endpoint Detection and Response) systems on laptops and servers, rightly considering them the first line of defense. However, this approach is akin to protecting a building by putting a guard at every door and window. This is absolutely crucial, but it leaves one fundamental question: what happens in the hallways, ventilation shafts and hidden service passages that connect all these rooms? What if the intruder is already inside?

This very visibility gap is being filled by Network Detection and Response (NDR) technology. It works like a sophisticated in-building surveillance system – a set of cameras, motion sensors and audio analyzers that constantly watch everything that moves on a company’s network. NDR doesn’t focus on what’s happening on a single device, but on how devices communicate with each other. In an era of sophisticated, multi-stage attacks, where hackers are quietly moving around the network, and the number of IoT and OT devices on which an agent cannot be installed is growing exponentially, network-level visibility is no longer a luxury. It is becoming an absolute necessity.

What exactly is Network Detection and Response (NDR) and what problem does it solve?

Network Detection and Response (NDR) is a category of cybersecurity solutions whose main task is to continuously monitor and analyze all traffic on a corporate network to detect and respond to malicious activity. Unlike EDR, which operates at the level of individual devices (endpoints), NDR provides a “bird’s eye” perspective, analyzing all communications flowing between servers, workstations, IoT devices and the Internet.

NDR solves one of the biggest problems facing today’s security teams: lack of visibility. Traditional security measures, such as firewalls, protect the edge of the network, while EDR protects key computer resources. However, there remains a huge “gray area” of devices on which an EDR agent cannot be installed. These include IP cameras, printers, smart sensors, and most importantly – critical industrial control systems (OT/ICS). For an attacker, these devices are ideal “blind spots” that he can use as a beachhead for further operations. NDR, being an agentless solution, provides insight into the activity of these devices, eliminating critical gaps in the defense.

How does NDR technology work and what data does it analyze?

The foundation of NDR technology is passive and non-invasive monitoring of network traffic. The solution does not install any software on the monitored devices. Instead, special sensors (physical or virtual) are connected to key points in the network infrastructure, such as SPAN (Switched Port Analyzer) ports on switches or network TAPs. In this way, the NDR receives a real-time copy of all traffic flowing through a given network segment.

Once captured, the data is analyzed in depth. Modern NDR platforms are not limited to analyzing basic information such as IP addresses and port numbers. They use Deep Packet Inspection (DPI) techniques to analyze packet contents, reconstruct application protocols and extract thousands of rich metadata. Not only the headers are analyzed, but the entire communication, which makes it possible to understand exactly what is going on in the network – who is talking to whom, what applications they are using and what data they are sending.

The most important element, however, is the analytics layer, based on Machine Learning. The NDR platform learns over a period of time what “normal” traffic looks like on a given unique network, creating a dynamic baseline model. Then, on a continuous basis, it compares current activity with this model, automatically detecting any anomalies or deviations that might indicate an attack.

Why is endpoint monitoring (EDR) not enough in the fight against advanced attacks?

Endpoint Detection and Response (EDR) systems have revolutionized security, providing unprecedented insight into what is happening on laptops and servers. They are absolutely essential, but relying solely on them creates dangerous gaps in defense strategy that sophisticated attackers can ruthlessly exploit.

The first and most important limitation is that an EDR agent cannot be installed everywhere. With the explosion in popularity of the Internet of Things (IoT) and the digitization of industry (OT), corporate networks are filling up with millions of devices on which installation of third-party software is impossible or prohibited by the manufacturer. We are talking about cameras, printers, televisions, building sensors or PLCs. To the EDR, these devices are invisible, and to a hacker they represent an ideal, unprotected target.

Second, sophisticated attackers are able to bypass or disable EDR agents. APT groups often spend a lot of time analyzing popular EDR solutions, looking for ways to disable them, hide their activity from their sensors, or use “living-off-the-land” techniques that are difficult to clearly classify as malicious. Finally, EDRs have limited insight into encrypted network traffic and do not see attempts to scan networks or attacks carried out from devices on which there is no agent.

What types of threats and attacks does NDR most effectively detect?

NDR’s strength lies in its ability to detect activities that are difficult or impossible to see from a single endpoint perspective. These platforms excel at identifying lateral movement (lateral movement). This is a technique that attackers use after gaining initial access to move silently around the network looking for valuable resources. NDR can detect unusual connections, such as when a workstation from the marketing department tries to connect to a database server in the finance department, which is highly suspicious activity.

NDR is also extremely effective at detecting communications with Command & Control (C2) servers. Even if malware evades detection by EDR, at some point it must connect to its “operator” on the Internet to retrieve commands or send stolen data. NDR, by analyzing all outbound traffic, can identify these hidden channels of communication based on the reputation of the targeted IP addresses, analysis of encrypted traffic (such as unusual SSL certificates) or anomalies in protocols.

What’s more, NDR is ideal for detecting the early stages of reconnaissance, such as port scans or attempts to query network services, which precede the actual attack. Because it can see the entire network, it can also identify attacks targeting “exotic” targets, such as the theft of data from a company printer or an attempt to take control of a CCTV system.

How do the NDR and EDR work together on the XDR platform?

The “NDR or EDR” debate is flawed at its core. The two technologies are not competitors to each other, but natural allies. Each provides a unique perspective, and their combination creates a much more complete and reliable picture. It is this synergy that is the foundation of modern XDR (Extended Detection and Response) platforms.

XDR is an evolution of EDR that integrates and correlates data from many different sources – not only from endpoints (EDR) and networks (NDR), but also from the cloud, email or identity systems. In this ecosystem, EDR and NDR mutually enrich each other’s context. Imagine a scenario: the EDR detects a suspicious PowerShell script on an employee’s laptop. By itself, this could be a medium-priority event. But at the same time, the NDR detects that the same laptop is making an unusual encrypted connection to a server on the Internet with a bad reputation.

The XDR platform automatically correlates these two alerts to create a single, highly reliable incident. The SOC analyst gets the full picture: he knows which process on the laptop (EDR data) is responsible for which suspicious network communication (NDR data). This allows for an instant and precise response, such as automatically isolating the infected laptop from the network before the attacker has time to do further damage.

How can nFlo help you select and implement an NDR-based strategy?

At nFlo, we see NDR as a key component of a mature security strategy that fills critical visibility gaps left by traditional tools. However, we understand that selecting and implementing the right solution can be a challenge. That’s why we offer comprehensive support, from analysis and design to implementation and operational management.

Our process begins with an analysis of the security architecture and identification of “blind spots.” As part of the audit, we help clients understand which areas of their network – especially segments with IoT and OT devices – are under-monitored and pose the greatest risk. Based on this analysis, we help select and implement an NDR platform that best suits the organization’s specifics, scale and budget. We make sure that the sensors are properly positioned and that the solution is integrated with the existing security ecosystem, especially with SIEM and EDR systems.

For companies that want to maximize the value from their NDR investment but don’t have a dedicated team of analysts, we offer MDR (Managed Detection and Response) services. Our Security Operations Center (SOC) monitors alerts generated by the NDR platform 24/7, and our experts are dedicated to analyzing anomalies, filtering out false alarms and investigating when real threats are detected. As a result, the customer receives not only technology, but most importantly peace of mind and the assurance that their network is under constant surveillance by specialists.