What Is Endpoint Detection and Response (EDR)?

According to the 2026 Kaseya State of the MSP Report, 71% of MSPs reported year-over-year cybersecurity revenue growth, and EDR has become the foundational security control clients expect as a baseline. The question is no longer whether you need EDR. It’s whether the EDR you have can handle what’s actually being thrown at endpoints in 2026.

Antivirus was the security standard for endpoint protection for decades. It worked well when malware was primarily known, signature-based, and delivered through predictable vectors. Against today’s threat landscape it provides minimal protection. Modern attacks use fileless malware that runs entirely in memory, living-off-the-land techniques that weaponize legitimate system tools, and polymorphic malware that changes its signature on every instance. None of these leave the kind of file footprint that signature-based detection can catch.

Endpoint Detection and Response (EDR) was built to close that gap. Rather than matching files against a database of known threats, EDR monitors endpoint behavior continuously and identifies the activity patterns associated with attacks, regardless of whether the specific technique has been seen before.

What Is EDR?

EDR is an endpoint security technology that continuously monitors endpoint activity, process execution, file modifications, network connections, registry changes, user account actions, and uses that telemetry to detect and respond to threats in real time.

The “detection and response” framing matters. EDR doesn’t just identify threats, it enables investigation and response. When a threat is detected, EDR provides the forensic data to understand what happened, how far the attack progressed, what was accessed, and what needs to be remediated. It also provides direct response capabilities: isolating the affected endpoint from the network, killing malicious processes, rolling back changes, and preventing further spread.

EDR has become the standard expectation for endpoint security in enterprise environments. It’s increasingly required by cyber insurance policies, mandated by compliance frameworks, and specified in security assessments as a baseline control. For MSPs, EDR is moving from an optional add-on to a standard component of managed service delivery, and increasingly, a prerequisite for getting clients insured.

How EDR Works

An IT administrator deploys an EDR agent on each endpoint. Once running, the agent observes processes, applications, network connections, and files, building a behavior baseline for the device over time. When activity falls outside that baseline, the agent flags it, reviews it for threat indicators, and responds or raises an alert depending on the severity.

A concrete example: if the EDR agent detects unusual child process creation under a legitimate application, an unexpected outbound connection on a non-standard port, or file encryption behavior across multiple directories simultaneously, it treats that behavioral pattern as a threat signal and acts on it before waiting for a file hash match against a known malware database.

When multiple alerts fire, EDR tools triage by severity, ensuring the most critical incidents reach security teams first. Post-remediation, the forensic function traces the full incident timeline: initial access vector, lateral movement, files touched, credentials accessed, providing the root cause data needed to prevent recurrence.

How EDR Differs from Antivirus

The difference comes down to detection method and scope.

• Antivirus compares files against a database of known malicious signatures. Effective against known, file-based malware. Cannot detect unknown threats, fileless attacks, or behavioral anomalies that don’t match a known pattern. By the time a new malware variant appears in the signature database, it has already been deployed in the wild.
  
• EDR monitors behavior across the entire endpoint, not just files, using a combination of rule-based detection, machine learning, and threat intelligence to identify both known threats and techniques that have never been seen before.

A fileless attack that injects malicious code into a legitimate process generates no file for antivirus to detect. An EDR monitoring process behavior sees the unusual child process, the unexpected network connection, the abnormal memory access, and fires on the behavior rather than a file.

In practice, EDR has replaced antivirus as the primary endpoint protection layer. Most modern EDR platforms include signature-based detection as a supplemental component, so you’re not choosing between them. You’re adding the behavioral layer that antivirus alone cannot provide.

Core EDR Capabilities

Continuous endpoint telemetry collection. EDR agents collect detailed logs of process execution, file operations, network connections, registry changes, and user account actions. This telemetry is the raw material for every detection, investigation, and threat hunt.

Behavioral threat detection. Detection rules and machine learning models identify attack patterns in the telemetry stream: lateral movement, privilege escalation, credential dumping, ransomware encryption behavior, and command-and-control communication. Detection is based on what the endpoint is doing, not which files are present.

Automated response and containment. When a threat is confirmed, EDR can respond immediately: isolating the affected endpoint from the network, killing malicious processes, blocking malicious connections, and quarantining files. This automation is what makes EDR a containment tool rather than just a detection tool. The response happens in seconds, not in however long it takes a technician to notice the alert.

Threat investigation and forensics. EDR telemetry provides a complete timeline of endpoint events: what ran, what it did, what files it touched, what connections it made. This data is essential for confirming the full scope of compromise, tracing the initial access point, and verifying every component of the attack has been removed before restoring the endpoint to production.

Threat hunting. In addition to automated detection, EDR supports proactive threat hunting, searching endpoint telemetry for indicators of compromise that automated rules may have missed. Threat hunting requires human analyst involvement, which is why EDR is often paired with MDR services for organizations without in-house security staff.

Reporting and compliance evidence. EDR generates detailed reports on detected threats, response actions, and endpoint security posture. For organizations subject to PCI DSS, HIPAA, Cyber Essentials, or CMMC requirements, this reporting provides the evidence trail auditors require.

What Threats Does EDR Protect Against?

Ransomware. EDR’s behavioral detection catches ransomware at the execution stage, identifying mass file encryption, shadow copy deletion, and command-and-control activity before encryption completes. Automated endpoint isolation contains the blast radius to a single device rather than letting it move laterally.

Fileless malware. Attacks that run entirely in memory using PowerShell, WMI, or other legitimate system tools leave no file for antivirus to detect. EDR’s process behavior monitoring detects the anomalous execution patterns regardless of whether any malicious file exists on disk.

Zero-day exploits. Because EDR detects on behavior rather than known signatures, it can identify exploitation attempts against unpatched vulnerabilities. The unusual process behavior that follows a successful exploit is detectable even when the exploit itself is entirely novel.

Multistage attacks and APTs. Advanced persistent threats unfold over weeks or months: initial access, quiet lateral movement, privilege escalation, data staging, and eventual exfiltration. EDR’s continuous telemetry means each stage leaves a record, and behavioral detection at any point can surface an attack that has been running quietly for some time.

Insider threats. Malicious insiders or compromised accounts misusing legitimate access are difficult to catch with perimeter tools. EDR’s baseline approach means unusual data access patterns, unexpected privilege usage, or abnormal file operations by a known account are flagged as anomalies rather than accepted as legitimate activity.

Phishing-delivered payloads. Phishing remains the most common initial access vector. EDR doesn’t stop the phishing email itself, that’s the role of email security tooling, but when a phishing-delivered payload executes on the endpoint, EDR detects the behavior and contains it before it can establish persistence or begin lateral movement.

EDR and the MITRE ATT&CK Framework

The MITRE ATT&CK framework is the industry-standard knowledge base of adversary tactics, techniques, and procedures observed in real-world attacks. It’s the reference framework for describing attack behavior, evaluating security tool coverage, and building detection logic.

When comparing EDR platforms, ATT&CK coverage is a more meaningful benchmark than headline detection rate claims. Two questions matter: which techniques does the platform detect reliably, and how accurately does it detect them without generating excessive false positives?

Focus on the tactics most relevant to your threat model. For most MSP-managed environments, the high-priority areas are initial access, execution, persistence, privilege escalation, credential access, lateral movement, and impact, which includes ransomware. An EDR with accurate coverage across those seven tactics provides substantially stronger protection than one that detects only known malware variants and calls it done.

EDR vs MDR: When You Need More Than a Tool

EDR is a powerful detection and response technology. It is not a fully managed security service. Detections that aren’t investigated and acted on provide no protection, and investigating EDR alerts accurately requires security expertise that most IT teams and MSPs don’t have available around the clock.

MDR (Managed Detection and Response) closes that gap by providing the human analyst layer on top of the EDR platform: security analysts who monitor telemetry, investigate alerts, triage false positives, and respond to confirmed threats, typically 24/7.

For organisations without in-house security operations capability, which describes most SMBs and a significant proportion of mid-market organisations, MDR makes EDR operationally effective. The technology detects. The MDR service determines what’s real, decides how to respond, and acts.

Datto EDR provides comprehensive endpoint detection and response including automated containment and full forensic investigation capability. For organizations that need the fully managed layer, Kaseya’s MDR service available in Kaseya 365 Endpoint Pro provides US-based security analysts operating 24/7 on top of the EDR platform. Explore Datto EDR or explore Kaseya 365 Endpoint for the full platform.

Choosing and Deploying EDR

• Detection coverage against MITRE ATT&CK. Which techniques are covered, and how accurately? Broad coverage with high false positive rates is less useful than precise coverage of the techniques that matter for your threat model.
  
• False positive rate. Alert fatigue is a real operational problem. An EDR that fires constantly trains analysts to tune it out, which is exactly how real threats get missed. Accuracy matters as much as sensitivity.
  
• Automated response depth. Can the platform automatically isolate endpoints, kill processes, and quarantine files without human approval for each action? Automated response speed is the difference between containing ransomware to one device and watching it spread. For MSPs managing multiple client environments, automation is the only way to respond at the speed threats require.
  
• Forensic investigation tooling. How easy is it to investigate a detection? Can you build a full event timeline, pivot from a process to every file it touched, or query telemetry across all managed endpoints for a specific indicator of compromise?
  
• RMM and PSA integration. For MSPs, EDR that integrates with the RMM provides unified visibility into endpoint health, security state, and active threats from a single operational console. Alert-to-ticket automation through PSA integration means detections enter the service delivery workflow rather than sitting in a separate security portal.
  
• Multi-tenancy and client segregation. For MSPs managing multiple client environments, the ability to view and act across all clients from one platform, with complete data segregation between them, is a non-negotiable operational requirement.