What Is EDR? Endpoint Detection and Response Explained

Your antivirus says everything is clean, but an attacker has been inside your network for six days. They've mapped your file shares, stolen credentials, and are about to deploy ransomware—much like the BridgePay attack that knocked out payment processing for days. Traditional antivirus never saw it coming because there was no malware signature to match—the attacker used living-off-the-land techniques with legitimate system tools.

This is the gap that endpoint detection and response (EDR) was built to close.

TL;DR

• What it is: Security software that continuously monitors endpoints to detect, investigate, and respond to threats that bypass traditional antivirus
• Why it matters: Attackers increasingly use fileless techniques and legitimate tools that signature-based antivirus can't catch
• Key takeaway: EDR gives security teams visibility into what's actually happening on endpoints—and the ability to act on it fast

What Is Endpoint Detection and Response?

Endpoint detection and response (EDR) is a category of security tools that continuously monitor endpoint devices—laptops, servers, workstations, and mobile devices—to detect suspicious behavior, investigate potential threats, and enable rapid response. Unlike traditional antivirus that relies on matching known malware signatures, EDR uses behavioral analytics, machine learning, and threat intelligence to spot anomalies that indicate compromise, even when no known malware is involved.

The term was coined by Gartner analyst Anton Chuvakin in 2013, who described it as a solution that "records and stores endpoint-system-level behaviors, uses various data analytics techniques to detect suspicious system behavior, provides contextual information, blocks malicious activity, and provides remediation suggestions."

How EDR Works

Think of EDR as a security camera system for every endpoint in your organization. It records everything, analyzes the footage in real time, and alerts you when something looks wrong.

Here's the process broken down:

1. Continuous Data Collection

EDR agents installed on each endpoint record a constant stream of telemetry: process executions, file modifications, registry changes, network connections, DNS lookups, command-line arguments, and user logins. This data gets sent to a central platform—usually cloud-based—for analysis.

2. Behavioral Analysis

Rather than checking files against a signature database, EDR looks at behavior patterns. If a PowerShell process spawns from a Word document, connects to an external IP, and starts downloading executables, EDR flags it regardless of whether those files match any known malware. This is what makes EDR effective against infostealers that target enterprise credentials and other threats that evade signature-based tools.

3. Detection and Alerting

When EDR identifies suspicious activity, it generates an alert with full context: what happened, which process started it, what files were touched, and which user account was involved. Security analysts can see the entire attack chain rather than just a single event.

4. Investigation

EDR platforms let analysts trace an incident backward and forward through time. You can see exactly how an attacker gained initial access, which systems they moved to, and what data they touched. Some platforms keep 90 days or more of historical telemetry, acting like a DVR you can rewind when you discover a compromise.

5. Response

This is where EDR earns its name. Response capabilities include isolating infected endpoints from the network, killing malicious processes, quarantining files, rolling back changes, and deploying new detection rules across all endpoints simultaneously. Some of these actions happen automatically; others require analyst approval.

EDR vs. Antivirus vs. EPP: What's the Difference?

These three terms get confused constantly. Here's how they actually differ:

Antivirus (AV) scans files against a database of known malware signatures. It's effective against commodity malware but blind to novel attacks, fileless techniques, and living-off-the-land binaries. Think of it as a bouncer with a list of known troublemakers—anyone not on the list walks right in.

Endpoint Protection Platform (EPP) is antivirus on steroids. EPP bundles signature-based detection with behavioral heuristics, application control, personal firewalls, and device management. It's focused on prevention—stopping threats before they execute. CrowdStrike defines EPP as the first line of defense that filters out the bulk of known threats.

EDR assumes some threats will get past prevention. It focuses on detection and response—finding attackers who are already inside and giving you the tools to stop them. EDR picks up where EPP leaves off.

In practice, most modern platforms merge EPP and EDR into a single agent. Forrester retired its standalone EDR evaluation in 2023, folding it into its XDR Wave because the market had converged. If you're evaluating tools today, you'll rarely find pure EDR—it comes bundled with prevention capabilities.

What About XDR?

Extended Detection and Response (XDR) takes the EDR concept beyond endpoints. Where EDR monitors laptops and servers, XDR correlates data across endpoints, email, cloud workloads, identity systems, and network traffic. The idea is to break down silos between security tools and give analysts a unified view of an attack across their entire environment.

XDR is where the market is heading. Gartner forecasts global security spending will grow 15% year over year, with endpoint and extended detection driving a significant share of that investment.

Key Capabilities to Look For

Not all EDR platforms are equal. When evaluating solutions, focus on these capabilities:

Real-time visibility — Can you see what's happening on every endpoint right now? Look for platforms that provide live process trees, network connections, and user activity without waiting for scheduled scans.

Behavioral detection — Signature-based detection is table stakes. You need behavioral analytics that catch fileless attacks, living-off-the-land techniques, and credential abuse. This matters especially as attackers use supply chain attacks and other methods designed to blend in with legitimate activity.

Automated response — Isolating a compromised endpoint in seconds versus waiting for an analyst to respond manually can be the difference between a contained incident and a full-blown ransomware attack. Look for platforms that support automated playbooks.

Threat intelligence integration — EDR should map detections to known adversary techniques using frameworks like MITRE ATT&CK. This context helps analysts understand who might be attacking them and what to expect next.

Forensic investigation — How far back can you look? When you discover a breach, you need to trace it to the point of initial access. Platforms that retain 30-90 days of telemetry are common; some offer longer retention for compliance-heavy industries.

Cloud-native architecture — On-premises EDR servers create management overhead and single points of failure. Cloud-native platforms deploy faster, scale better, and don't require you to maintain additional infrastructure.

The EDR Market in 2026

The EDR market has grown aggressively. According to Mordor Intelligence, the global market hit $5.1 billion in 2025 and is projected to reach $18.68 billion by 2031, growing at a 24.15% CAGR. North America accounts for about 37% of that market.

Several factors are accelerating adoption. U.S. federal mandates now require civilian agencies to deploy EDR, and those requirements have expanded to cover cloud workloads and identity systems. Recent directives like CISA's BOD 26-02 on edge device replacement signal that the government is getting more aggressive about endpoint security requirements across the board. The private sector is following suit—cyber insurance policies increasingly require EDR as a minimum security control before they'll underwrite a policy.

Major vendors in the space include CrowdStrike, Microsoft Defender for Endpoint, SentinelOne, Palo Alto Cortex XDR, and Cisco Secure Endpoint. Each takes a slightly different approach, but they've all converged around the core capabilities listed above.

When Do You Need EDR?

If your organization has more than a handful of endpoints, you probably need EDR. Here's a rough guide:

• Small teams (under 25 endpoints): A quality EPP with built-in EDR features might be enough. Many modern platforms include basic detection and response in their standard tier.
• Mid-size organizations (25-500 endpoints): EDR becomes critical. You have enough attack surface that threats will get past prevention, and you need the visibility and response capabilities to handle them.
• Enterprises (500+ endpoints): XDR is worth evaluating. At this scale, correlating signals across endpoints, email, identity, and cloud workloads gives you significantly better detection fidelity.

For organizations without a dedicated security team, Managed Detection and Response (MDR) services operate EDR on your behalf. NIST defines MDR as outsourced monitoring and response—you get the benefits of EDR without needing to staff a 24/7 security operations center.

Frequently Asked Questions

Can EDR replace antivirus?

Most EDR platforms include antivirus capabilities, so yes—in many cases you can replace standalone antivirus with an EDR solution that handles both prevention and detection. That said, some compliance frameworks specifically require "antivirus software," so check your regulatory requirements before dropping a named AV product.

Does EDR slow down endpoints?

Modern EDR agents are lighter than they used to be. The performance impact is usually negligible for typical office workloads—1-3% CPU overhead in most cases. High-performance computing or latency-sensitive systems might need fine-tuned exclusion policies, but for most deployments, users won't notice the agent running.

How is EDR different from a SIEM?

A SIEM (Security Information and Event Management) collects and correlates log data from across your entire environment—firewalls, servers, applications, cloud services. EDR focuses specifically on endpoint telemetry. They're complementary: EDR feeds detailed endpoint data into your SIEM for broader correlation. Most organizations with mature security programs use both.

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