Antivirus vs EDR vs MDR: Which Endpoint Protection Do You Need?
Antivirus, EDR or MDR? Detection, response, 24/7 monitoring, in-house skills and cost model compared for small businesses with 10, 50 or 150 employees.
Facts verified : October 2026This comparison is not sponsored.
Our recommendation for your situation
10-person office on Microsoft 365 with a part-time IT provider
EDR
EDR is already included if you're on Microsoft 365 Business Premium. Get your IT provider to commit in writing to receiving alerts and to a response time, weekends included.
50-person Mississauga engineering firm with nobody dedicated to security
MDR
At this size, nobody has time to triage alerts, let alone overnight. MDR brings 24/7 monitoring; keep one person in-house who knows your systems and can approve a response.
150-employee manufacturer with a small in-house IT team
MDR
The internal team keeps control of devices and patching; MDR covers evenings, weekends and alert analysis. The Canadian Centre for Cyber Security presents exactly this kind of reinforcement as a benefit of managed services.
Side-by-side comparison
Criterion
Traditional antivirus
EDR
MDR
Detection approach
Signatures of known malicious code
Continuous analysis of workstation and server behaviour
Detection tool (often EDR) plus analysts who validate alerts
Catches an intrusion with no known malicious code
Unlikely
Yes, through abnormal activity
Yes, with human analysis on top
Response capability
Quarantine or delete the detected file
Contain and remediate the device, manually or automatically
Analysts act or notify you, depending on the contract
Who watches alerts 24/7
Nobody, unless the antivirus is centrally managed
Your IT team or provider, during its hours
The provider's security operations centre
In-house skills required
Low: check that protection is on and up to date
High: configure, triage alerts, investigate
Moderate: someone who knows your systems and can approve a response
Evidence for investigation and reporting
Limited to detections
Device activity logs (EDR logs)
EDR logs plus the provider's incident reports
Typical cost model
Included in the operating system, or a per-device licence
Per-device or per-user licence, sometimes included in the productivity bundle
Quoted service subscription
What the authorities say
Baseline control for every SMB (Canadian Centre for Cyber Security)
Recommended by CISA; worth considering according to the Canadian Centre
24/7 monitoring cited by the Canadian Centre as a benefit of managed security services
Main risk
An intrusion using no known code goes unnoticed
Alerts nobody reads at night or on weekends
A vague contract about what the provider actually does
Managed detection and response: an outside team watches your detection tools around the clock, investigates and responds as set out in the contract.
Best for
Businesses with no security team that want a 2 a.m. alert handled before the office opens.
Pricing
Service subscription, usually quoted, on top of the detection tool or bundled with it
Strengths
24/7 monitoring by a security operations centre, with no hiring
Analysts validate alerts before bothering you
Strengthens a small in-house IT team rather than replacing it
Limitations
A cost the Canadian Centre for Cyber Security says can be prohibitive for some organizations
You hand monitoring to a third party, but the risk and the accountability for incident response stay with you
Outside analysts know your systems less well than an internal team (NCSC)
"We have antivirus, so we're fine." That's often the first thing a small business owner says when endpoint protection comes up. The trouble is that today's attacks rarely involve a file antivirus recognizes. The intruder signs in with a stolen password, uses the admin tools already on the network and takes their time.
Antivirus, EDR and MDR aren't three competing brands. They're three layers of protection that stack on top of each other. This comparison helps you pick the right layer for your size and resources. To compare EDR products themselves, see our EDR comparison for small businesses.
Our method
We compare approaches, not products. Every value in the table is based on publications from the Canadian Centre for Cyber Security, CISA and the UK NCSC, reviewed in October 2026.
Criteria: detection approach, response capability, 24/7 monitoring, skills required, evidence for investigation, cost model and what the authorities recommend.
No prices are quoted: cost models are described qualitatively.
Antivirus is still a must. The Canadian Centre for Cyber Security's baseline controls ask every small and medium organization to run anti-malware that updates and scans automatically. The good news: the antivirus built into Windows and macOS, switched on and up to date, can fill that role. The UK NCSC even says it will meet the needs of many organizations.
Its limit is its method. Traditional antivirus compares files against signatures of known malicious code, and the NCSC notes that advances in malware have limited how well that works. CISA, for its part, observes that many organizations lack the capabilities to detect attackers who "live off the land," using legitimate tools already on the system. Antivirus sees very little of that.
EDR continuously watches what happens on workstations and servers: processes launched, connections, file changes. The Canadian Centre for Cyber Security recommends considering EDR, or XDR, to detect and respond to abnormal system activity, and lists EDR logs among the security logs that matter when an incident occurs. Depending on the product, EDR can also roll a device back to its pre-infection state. In its ransomware guide, CISA recommends application allowlisting and/or EDR on all assets.
The catch: the Canadian Centre classes EDR among advanced controls that require additional resources. A poorly configured EDR, or one whose alerts nobody reads, reassures without protecting. Read our anatomy of a ransomware attack: all it takes is an alert that fires at 11 p.m. on a Friday and gets read Monday morning.
MDR answers one question: who's watching? An outside team monitors your detection tools around the clock, validates alerts and either acts or notifies you, depending on the contract. The Canadian Centre for Cyber Security lists this continuous monitoring among the benefits of managed security service providers, along with lower costs than hiring in-house specialists.
It also names the downsides. The cost can be prohibitive for some organizations. You hand monitoring to a third party, but you still own the risk and remain accountable for incident response. The UK NCSC adds that an outside team knows your systems less well and may respond more slowly than an internal one. That's why the contract matters: guaranteed response times, how you're notified, what the provider may do without your approval, and where your logs are stored.
Start with a simple question: if an attack starts at 2 a.m. on a Saturday, who notices, and when?
Under 15 employees, part-time IT provider: EDR, often already paid for in your Microsoft 365 plan, with alerts routed to the IT provider and a written response time.
25 to 100 employees, nobody dedicated to security: MDR. Triaging alerts quickly takes more time than a generalist IT provider can give.
Over 100 employees with an IT team: MDR that backs up the team in the evenings, on weekends and during holidays.
Everywhere: keep the built-in antivirus on every device, including those EDR doesn't cover.
Before signing with an MDR provider, ask at least these questions: do you act, or only alert? Within how many minutes? Who do you call on our side at night? Where are our logs stored? The answers will also help you with your cyber insurance questionnaire.
Not sure your EDR really covers every workstation and server, or who receives its alerts? Our cybersecurity audit checks it device by device and gives you a prioritized plan.
Frequently asked questions
What's the difference between antivirus and EDR?+
Antivirus mainly looks for known malicious code and quarantines it. EDR continuously monitors device behaviour to spot abnormal activity, even with no known malicious file, and lets you respond remotely. Don't run two antivirus products on the same device: the UK NCSC warns they can conflict. Check with the vendor how its EDR coexists with the built-in antivirus.
Is Microsoft Defender enough for a small business?+
The Microsoft Defender Antivirus built into Windows covers the baseline control. For EDR, you need Microsoft Defender for Business, included in Microsoft 365 Business Premium or sold separately. Either way, the key question is the same: who reads the alerts, and how fast?
Does an MDR service replace our IT provider?+
No. MDR monitors threats and responds; your IT provider still manages devices, patching and backups. The Canadian Centre for Cyber Security reminds organizations that they remain accountable for incident response, so the contract should spell out response times, how you're notified and what the provider may do without your approval.
Is XDR better than EDR?+
XDR extends detection beyond devices to email, cloud accounts and the network. The Canadian Centre for Cyber Security mentions it alongside EDR, but there's no single official definition and the scope varies from vendor to vendor. Ask which data sources are actually covered rather than trusting the label.