Antivirus blocks known threats by matching file signatures and hashes — prevention based on databases. EDR (Endpoint Detection and Response) analyses process behaviour, records telemetry, detects unknown attacks and provides response tools: host isolation, remediation and investigation. In short, antivirus prevents known malware, while EDR detects and responds to unknown and targeted attacks.
Key differences between EDR and antivirus
Traditional antivirus (AV) works like a gate filter: it compares files against a database of signatures and reputation hashes and blocks anything already known to be malicious. It is a fast, cheap way to stop commodity threats, but it is powerless against attacks that never touch the disk and against techniques not yet in the database. EDR is built differently — it continuously collects telemetry from the endpoint (process launches, network connections, registry changes, memory access) and looks for suspicious chains of behaviour rather than individual "bad" files.
The critical word in the acronym is Response. Antivirus can only delete a file or move it to quarantine. EDR adds active response: isolating an infected host from the network, killing malicious processes, collecting artefacts for investigation and rolling back some changes. That is why EDR is classed as a detection-and-response tool rather than a purely preventive control.
The signature approach loses for a fundamental reason: an attacker only has to change one byte or repack the malware to get a new hash and slip past the database. Polymorphic and metamorphic malware, packers and payload generators do this automatically. Behaviour is far harder to change: to steal credentials from memory or encrypt files, the attack still performs recognisable actions — and those are exactly what EDR records.
| Criterion | Antivirus (AV) | EDR |
|---|---|---|
| Detection method | Signatures, hashes, file reputation | Behavioural analysis, heuristics, ML, IOC/IOA |
| Response | Delete and quarantine a file | Host isolation, process termination, rollback, fleet-wide search |
| Visibility | A single "file blocked" event | Full telemetry and an attack timeline |
| Threat coverage | Known viruses, trojans, commodity malware | Fileless attacks, living-off-the-land, ransomware, APTs |
| Cost | Low, usually per device | Higher: licences + data storage + analysts |
| Management | Install and forget | Needs a SOC team or an MDR service |
What each one detects
Antivirus is good at catching what is already documented: known families of viruses, trojans and worms, adware and potentially unwanted programs, malicious email attachments. Modern AV is augmented with cloud reputation and heuristics, but its logic stays file-centric — "is this object on the bad list?".
EDR targets the attack technique, not a specific sample. It surfaces what leaves no file or masquerades as legitimate tooling: fileless attacks in memory, PowerShell and WMI abuse, living-off-the-land techniques, lateral movement, credential theft and ransomware staging. The MITRE ATT&CK matrix documents these tactics and techniques (for example, T1055 Process Injection, T1003 Credential Dumping), and EDR is tuned to exactly these behavioural indicators of attack (IOAs).
Another key difference is data depth. Antivirus records the fact of a block and stores almost nothing. EDR keeps telemetry for weeks or months, which lets you investigate an incident after the fact: understand how the attack entered, which hosts are affected and what must be remediated. That retrospective matters because the average dwell time of targeted attacks is measured in weeks, not minutes.
There is a flip side. The broader the behavioural detection, the higher the risk of false positives: a legitimate administrator running PowerShell scripts looks much like an attacker abusing the same tools. EDR therefore needs rule tuning and human triage, whereas a signature-based antivirus generates almost no false alarms but misses everything genuinely new.
- Antivirus: known malware, signature and hash matches, mass campaigns.
- EDR: unknown and targeted attacks, behavioural anomalies, post-exploitation.
Do you still need antivirus if you have EDR
In practice the line is blurred: most modern EDR platforms include a next-generation antivirus (NGAV) engine as a built-in prevention layer. A separate classic antivirus running alongside a full EDR is usually redundant and even harmful — two agents hooking the same events conflict with each other and hurt performance.
The right model is defense in depth: a preventive layer (NGAV) blocks what can be blocked cheaply and instantly, while the detection-and-response layer (EDR) catches the rest. NIST guidance on incident handling (SP 800-53, SP 800-61) assumes that prevention is never perfect, so organisations need detection and response capabilities, not prevention alone.
NGAV (next-generation antivirus) — where it fits
NGAV (Next-Generation Antivirus) is the middle ground between classic AV and EDR. It stops relying on signatures alone and adds machine learning, behavioural blocking and cloud analysis to stop unknown samples at execution time. But NGAV, like any antivirus, is prevention-focused: it blocks the threat but does not provide deep telemetry, an attack timeline or investigation tooling.
EDR, by contrast, emphasises visibility and response after a breach. In most commercial products NGAV and EDR ship as a single agent: NGAV is the preventive layer, EDR is the detective-and-response layer. Gartner defines EDR as a distinct category, alongside consolidated endpoint protection platforms where NGAV and EDR are parts of one product.
What to choose for a business
The choice depends on maturity, risk and available people, not just budget:
- Small business with no security staff: NGAV at a minimum; EDR only as a managed offering (see below), otherwise no one triages the alerts.
- Mid-size business with an IT team: EDR with NGAV in one agent, plus an MDR service if there is no in-house SOC.
- Large or regulated organisation: EDR as the foundation, integrated with a SIEM and SOC, threat hunting and NIST-aligned response processes.
Consider the operational load separately. EDR generates alerts that must be prioritised, investigated and closed. Without processes and people the alert stream becomes noise and alert fatigue. For many companies the optimal answer is therefore not bare EDR but EDR + MDR, where an external 24/7 team owns detection and response.
The core point: EDR does not replace antivirus — it absorbs and extends it. The danger is not the "AV or EDR" choice, but buying EDR with no resource to handle its alerts. If you have no team of your own, a managed service is the wiser buy than paying for telemetry that no one reads.
To summarise: antivirus and EDR are not competitors but different layers of one model. Antivirus, in the form of NGAV, cheaply filters out the known, while EDR adds visibility, behavioural detection and response to whatever prevention missed. For a business the question is not "AV or EDR" but "do we have the processes and people to make EDR pay off?" — and that answer matters more than the choice of any particular vendor.
For more on the technologies themselves and related approaches, see our guides: what is EDR, what is MDR (managed detection and response) and what is SIEM for centralised event collection.
FAQ
Is EDR a replacement for antivirus?
Functionally yes: EDR platforms include an NGAV engine that plays the role of preventive antivirus. You should not run a separate classic AV alongside it — that creates agent conflicts. But "replacement" here means absorption: EDR does everything AV does and adds detection and response.
Can I use antivirus alone?
For a home computer, yes. For a business it is risky: antivirus cannot see fileless or targeted attacks and gives you no data for investigation. NIST assumes prevention is never perfect, so organisations need detection and response as well.
How is EDR different from XDR?
EDR operates at the endpoint level. XDR (Extended Detection and Response) extends the same logic to email, network, cloud and identity, correlating events from several sources. XDR is the evolution of EDR beyond a single host.
Do you need a SOC for EDR?
Technically EDR can be deployed without a SOC, but its value lies in triaging alerts and responding, and that is human work. Without a SOC or an MDR service, EDR alerts go unhandled and you pay for telemetry that no one reads.
What is behavioural detection?
It is spotting threats by their actions rather than by a file: suspicious process chains, memory injection, anomalous network connections. These indicators of attack (IOAs) are described in the MITRE ATT&CK matrix and underpin EDR detection.
Does EDR protect against ransomware?
EDR recognises the tell-tale behaviour of ransomware (mass file changes, deletion of shadow copies) and can isolate a host before it spreads. That is more effective than signature-based antivirus, which only sees ransomware samples that are already known.