EDR vs antivirus: what actually changed and what still matters

Cyber insurance renewal questionnaires in 2025-2026 include a question that earlier versions did not: “Does the organization deploy Endpoint Detection and Response (EDR) or Managed Detection and Response (MDR) across all endpoints?” A common answer, “Yes, we have Windows Defender”, is not the answer underwriters are looking for and applications relying on that answer have been returning with premium increases in the 20-30% range or with exclusions that reduce the policy’s practical value during an incident.

Defender (the built-in consumer antivirus) is a competent product. It is not EDR. Understanding why that distinction matters and what the cyber insurance market expects, is one of the most common conversations happening in mid-market IT right now.

Antivirus, what it actually does

Traditional antivirus has one job: detect known-bad files. It works by maintaining a signature database of malware, scanning files against that database on download or execution and blocking or quarantining matches. When a new piece of malware appears in the wild, security researchers analyze it, publish a signature and every AV product that consumes that signature update gains the ability to detect it.

This model worked well in 2005. It works poorly in 2026 because attackers stopped relying on static file signatures years ago. Modern intrusions typically involve:

• Living-off-the-land techniques, using legitimate Windows tools (PowerShell, WMI, scheduled tasks) in attacker-controlled ways. No malicious file to scan.
• Credential abuse, logging in through legitimate remote access channels with stolen credentials. No malware on the endpoint at all.
• Fileless in-memory techniques, injecting code into running processes. Nothing touches disk.
• Custom or rapidly-mutating malware, produced specifically for a target or rotated faster than AV signatures can catch up.

Against any of these, a traditional AV engine returns a “clean” scan while an attacker moves laterally through the network. Published mid-market breach post-mortems routinely show clean antivirus consoles coexisting with active attacker dwell time measured in weeks, no malware detections, while credentials are harvested and data is staged for exfiltration.

EDR, what changed

EDR, Endpoint Detection and Response, is a fundamentally different category. Rather than asking “is this file on a bad list,” EDR continuously records endpoint behavior (process creations, network connections, registry modifications, script executions, user logons) and applies behavioral analytics to spot patterns that look like an attack in progress. When the system detects suspicious behavior, it alerts and, depending on configuration, can automatically isolate the endpoint, terminate the process or trigger a response playbook.

The practical difference:

• A traditional AV might or might not detect a novel ransomware strain executing in-memory.
• An EDR notices the same endpoint that just ran a suspicious PowerShell command, connected to an unfamiliar external IP and started encrypting files at high volume and stops it in the middle.

Leading EDR products in the mid-market, CrowdStrike Falcon, Microsoft Defender for Endpoint (which is genuinely EDR, not “regular” Defender), SentinelOne, Sophos Intercept X, Huntress, operate on this model. Pricing has come down substantially over the last three years; current mid-market pricing typically lands between $5 and $12 per endpoint per month, inclusive of central management and reporting.

MDR, the next step

MDR is EDR plus a managed Security Operations Center watching the alerts. EDR by itself is a tool; MDR is that tool plus human analysts reviewing alerts, triaging incidents and responding around the clock. For organizations without a dedicated internal security team, which is most organizations under 500 employees, MDR is the practical deployment model.

Our managed tier offerings include MDR as standard at the Advantage tier. Without MDR, an EDR deployment creates alerts that either get ignored or generate alert fatigue for a small internal IT team. With MDR, alerts are triaged by analysts trained on the product, with hours of operation that cover nights, weekends and holidays, which is exactly when ransomware campaigns prefer to operate.

What the cyber insurance market expects

As of 2026, cyber insurance carriers serving mid-market businesses largely require or strongly prefer EDR for favorable pricing. The specific questionnaire wording varies by carrier, but the underlying question is the same: “do you have behavioral endpoint protection, not just signature-based antivirus.”

Organizations answering “yes, we have Windows Defender” (the built-in home version) are increasingly finding their applications rated as higher risk. Organizations answering “yes, we have Microsoft Defender for Endpoint”, which is EDR, or “yes, we have CrowdStrike / SentinelOne / Huntress” receive meaningfully better pricing and fewer exclusions.

Deployment realities

For a 40-person firm deploying EDR for the first time, the rollout is typically:

• Week 1, tool selection and tenant setup. EDR agents deployed to a pilot group of 5-10 machines. Baseline monitoring established.
• Week 2, full-organization rollout via Group Policy, Intune or the RMM of choice. Usually completed in one business day.
• Weeks 2-4, alert tuning. Every environment generates some false positives in the first month as the behavioral baseline establishes. Tuning these down is part of the engagement.
• Month 2 onward, ongoing monitoring, incident response when alerts surface, monthly reporting.

If MDR is part of the deployment, alert triage is handled by the managed service. If not, an internal team owns the alerts, which works for organizations with mature internal security operations and less well for most small and mid-market firms.

What still matters (and what EDR does not solve)

EDR is a necessary control for a modern cybersecurity program. It is not a complete program. Controls that remain essential alongside EDR:

• Tested backups with immutability, EDR can stop many ransomware attacks; backups are your fallback when it does not.
• MFA on all remote access and administrative accounts, EDR detects behavior on the endpoint; MFA prevents the credential abuse that leads an attacker to the endpoint in the first place.
• Network segmentation, keeps a compromised endpoint from reaching production systems.
• Incident response planning, an EDR alert at 3 a.m. is only useful if someone knows what to do with it.
• Cybersecurity awareness training, reduces the phishing clicks that initiate most intrusions.

Cyber insurance questionnaires typically ask about all of these alongside EDR. Deploying EDR in isolation improves your posture significantly; deploying it alongside the other controls is what produces the evidence a carrier or customer actually wants to see.

If your cyber insurance renewal is coming up and the EDR question is surfacing or if your current antivirus stack is still signature-based, schedule a discovery call. We can scope the right deployment for your environment and timeline.