What Is EDR and Does a Small Business Need It?

What EDR actually watches for

Traditional antivirus asks a simple question: does this file match a known bad signature. EDR asks a broader question: is this process behaving the way malware behaves, regardless of whether it has been seen before. That includes things like a Word document spawning a command-line process, a program suddenly encrypting hundreds of files in sequence, or a piece of software making an unusual connection to an unfamiliar server.

This behavioural approach catches attacks that have never been seen before anywhere, which is important because attackers routinely modify malware slightly specifically to evade signature-based detection.

How EDR responds once it detects something

• Isolating the affected device from the network automatically to stop spread
• Killing the malicious process before it completes its objective
• Recording a detailed timeline of what happened for investigation afterward
• Alerting a security team, whether internal or an outsourced monitoring service

EDR is a tool, not a team

One detail that gets glossed over in marketing is that EDR software generates alerts, and someone still needs to review and act on those alerts. A small business that installs EDR but has nobody watching the console is only marginally better protected than before, since a genuine attack in progress still needs a human decision to isolate a device or investigate further.

This is why EDR is commonly paired with a managed detection and response service, where a security team reviews and acts on alerts around the clock rather than the alerts simply queuing up unread. Our page on managed detection and response covers how that oversight works in practice.

Does a small business actually need it

Not every business needs the most advanced EDR platform on the market, but most small businesses handling client records, payment details, or any remote access to their network get meaningful value from it, particularly compared to consumer-grade antivirus alone. Businesses in regulated fields such as legal, healthcare, or accounting see it come up as an expectation from clients and insurers even before they consider it internally.

How EDR fits with cyber insurance

EDR has become one of the most commonly asked-about controls on Ontario cyber insurance applications. Insurers increasingly treat traditional antivirus as insufficient on its own for meaningful ransomware coverage. If you are preparing for a renewal, our cybersecurity checklist for Ontario businesses covers the broader set of controls insurers typically ask about alongside EDR.

EDR versus antivirus in practical terms

The line between antivirus and EDR has blurred somewhat as vendors bundle both into a single product, but the practical difference in what each catches and how each responds is still significant enough to matter when comparing options. Our article on endpoint security versus antivirus breaks that comparison down in more detail.

What to look for when evaluating an EDR product

• Whether it includes automated isolation of a compromised device, not just alerting
• Whether alerts are actually monitored, either internally or by a managed provider
• Coverage across servers as well as workstations, since servers are common targets
• Integration with your existing firewall and email security so incidents can be correlated

Where this fits in a broader security plan

EDR addresses what happens once something has already reached a device. It works alongside, not instead of, controls that reduce the chance of reaching that point in the first place, such as multi-factor authentication, email and collaboration security, and a properly configured business firewall. No single control, EDR included, is a complete answer on its own.

Sources and further reading

• Canadian Centre for Cyber Security
• NIST Computer Security Resource Center

Frequently asked questions