EDR vs Antivirus: Do You Still Need AV?

Antivirus asks "is this file bad?" at the moment it runs, while endpoint detection and response (EDR) asks "what is happening on this machine, and what happened before?", and teams still buy, tune and staff them as if they were the same thing. The difference decides whether you can investigate an intrusion, contain a host remotely and catch hands-on-keyboard attackers who use legitimate tools. This guide compares the two directly: what each does, a side-by-side table, when antivirus alone is enough, how they run together on the same endpoint, and the mistakes that leave gaps. It is written for endpoint, SOC and security architecture teams choosing or rationalising endpoint protection. For EDR operations in depth see the EDR Guide, and for modern prevention engines see the Next-Generation Antivirus (NGAV) Guide.

Key takeaways

Short answer: you still need prevention, and most organisations also need EDR. Antivirus (signature plus next-generation engines) blocks known and likely-malicious code before it runs; EDR records endpoint activity, detects attacker behaviour and gives you remote response. They solve different problems.
EDR is defined by telemetry and response, not by blocking. OMB memorandum M-22-01 describes EDR as combining real-time continuous monitoring and collection of endpoint data with rules-based automated response and analysis.
Most EDR platforms now ship with antivirus built in. The real choice is usually one agent that does both versus a separate antivirus product beside an EDR sensor, and the second option needs careful mode settings to avoid conflicts.
Antivirus alone fits narrow cases. Locked-down devices that can only run approved software, small organisations with no one to answer alerts, and platforms where the NCSC says AV adds little value.
EDR without people is antivirus with extra cost. Its value comes from triage, hunting and response. Without a SOC or a managed detection and response (MDR) service, alerts go unread.

What each one is

Antivirus (also anti-malware, endpoint protection) scans files and processes on access, on demand and on schedule, compares them with signatures, heuristics, machine learning models and cloud reputation, and blocks, quarantines or removes what it judges malicious. NIST SP 800-83 Rev. 1, Guide to Malware Incident Prevention and Handling for Desktops and Laptops, treats it as a core prevention control. Next-generation antivirus (NGAV) extends the engines with behaviour monitoring and cloud analysis, but its job is still to make a verdict and stop execution. In ATT&CK it is mitigation M1049 Antivirus/Antimalware.

EDR places a sensor on each endpoint that continuously records process creation, command lines, file, registry, network and authentication events, sends them to a central platform, runs behavioural detections across that history, and lets responders act remotely: isolate the host, kill a process, collect files, run scripts, roll back changes. It is built for the activity antivirus does not judge malicious on its own, such as an administrator tool used by an attacker, PowerShell running an encoded command (T1059.001) or credential theft from LSASS memory (T1003.001). XDR extends the same model across identity, email, cloud and network telemetry; see the XDR Guide.

Side-by-side comparison

Dimension	Antivirus (including NGAV)	EDR
Core question	Is this file or process malicious?	What is happening and what happened on this endpoint?
Main outcome	Prevention: block, quarantine, clean	Detection, investigation and response
Data kept	Detections and scan results	Continuous event telemetry, retained for search and hunting
Detection method	Signatures, heuristics, ML file models, cloud reputation	Behavioural analytics, correlation across events and hosts, threat intelligence, custom detection rules
Strong against	Commodity malware, known ransomware binaries, malicious documents	Living off the land, hands-on-keyboard intrusions, lateral movement, credential theft
Response actions	Local quarantine and removal	Remote isolation, process kill, file collection, live response, rollback (product dependent)
Who uses it	Runs largely unattended; IT reviews detections	SOC analysts, threat hunters, incident responders, or an MDR provider
Operating cost	Low: updates, exclusions, occasional triage	Higher: alert triage, tuning, data retention, response playbooks
Typical failure	Misses novel or fileless techniques	Alerts nobody reads; sensor gaps on servers and unmanaged hosts

When antivirus alone is enough, and when you need EDR

Situation	Recommended	Reason
Corporate Windows, macOS and Linux fleet with admins and remote access	EDR with built-in prevention	Intrusions use valid tools and credentials that file verdicts miss
Servers, domain controllers, jump hosts	EDR, prevention tuned for server roles	High-value targets where you need history and isolation
Small organisation, no security staff	Built-in or managed antivirus, plus EDR only through an MDR service	Unattended EDR adds cost without response
Kiosks and single-purpose devices with application allow-listing	Allow-listing first; antivirus optional	NCSC notes AV offers very limited value when devices cannot run unknown code
Chrome OS, Android, iOS in default configuration	Platform protections and mobile device management	NCSC says you should not need AV on these in their default configuration
US federal civilian agency	EDR aligned with CISA	OMB M-22-01 directs agencies to deploy EDR and give CISA access for threat hunting
Home users	Built-in antivirus kept updated	See Antivirus for Home Users

Small vs large organisations: a small business gets most of the value from built-in antivirus, application control, patching and MFA, and should buy EDR as a managed service if at all. A large enterprise needs EDR on every supported endpoint and server, with searchable telemetry retained long enough for its own investigations and a staffed or outsourced 24x7 response function.

Running both on the same endpoint

Most organisations end up with prevention and EDR together. There are two patterns.

One agent for both: the EDR product's own prevention engine is the primary antivirus. One policy, one update stream, no conflicts. Make sure prevention policies are set to block, not detect only.
Separate antivirus beside an EDR sensor: often during migrations or where a sector product is mandated. Only one product should be the active real-time scanner. The NCSC advises against running more than one antivirus product on a device because the products may conflict and cause stability problems.

Many EDR platforms can run alongside a built-in or third-party antivirus, with one product set as primary and the other in a passive or monitor-only mode. In passive mode the secondary engine typically stops remediating, and some of its preventive features stop working. Some platforms also offer a block mode in which the EDR remediates behavioural detections the primary antivirus missed, usually with licence and configuration prerequisites. Servers often need passive mode set explicitly before onboarding, and disabling the operating system's security centre service to force coexistence can leave both engines active, which vendors generally do not support. Check each vendor's coexistence documentation before deploying two agents.

Security trade-offs

Prevention vs visibility: blocking early is cheaper than responding later, but a block with no telemetry leaves you blind to what came before and after. EDR gives you the timeline you need for scoping and notification decisions.
Privilege and attack surface: both run as highly privileged kernel or system components. Attackers target them with T1685 Disable or Modify Tools and vulnerable drivers. Turn on tamper protection; see the Bring Your Own Vulnerable Driver and EDR Killers Guide.
Exclusions: every antivirus or EDR exclusion is a place malware can hide. Keep them narrow and reviewed; see the EDR Tuning and Exclusions Management Guide.
Privacy and data: EDR collects command lines, file names and user activity. OMB M-22-01 itself requires EDR deployments to comply with applicable privacy law; in the UK and EU, run a data protection impact assessment and set retention.
Response power is a privilege: live response consoles can run scripts on every endpoint. Treat EDR console roles as privileged access.

Where identity fits

The EDR console and its API are among the most powerful identities in the estate: an account that can isolate hosts or run live response scripts can also be used to disable protection or push code. Protect console roles with phishing-resistant MFA and privileged access controls, and govern the API clients and service accounts that SOAR and SIEM integrations use to call the EDR API as non-human identities with scoped permissions and rotated secrets. Vendor tamper protection guidance generally asks for least privilege on the roles that can change protected settings. EDR telemetry also feeds identity detections such as credential dumping (T1003.001). See the EDR and XDR platform health check.

Moving from antivirus to EDR

Inventory endpoints: list every OS and server role, and mark which can run the sensor. Unsupported or unmanaged hosts are your blind spots.
Decide the prevention model: one agent, or keep the existing antivirus as primary with the EDR sensor alongside, and set the coexistence mode before deployment.
Pilot ring: deploy to IT and security staff and a sample of each server role in audit or detect-only mode for two to four weeks; record performance impact and false positives.
Tune, then block: add narrow exclusions with owners, then switch prevention and automated response to block ring by ring.
Build response: write playbooks for isolation and containment, agree who may isolate a production server, and connect alerts to your SIEM or MDR.
Remove the old antivirus last: only after the new prevention is active and verified on each ring. Rollback is re-enabling the old product's real-time protection on that ring, so keep its management console until the last ring is done.

For a full migration plan see the EDR and XDR platform migration playbook.

Detection and measurement

Sensor coverage: share of managed endpoints and servers with a healthy, reporting sensor, reconciled against the asset inventory (target above 98%).
Prevention mode: share of endpoints with real-time protection on and prevention set to block.
Tamper events: count of tampering attempts and time to investigate each.
Mean time to acknowledge and to contain: from high-severity alert to analyst action and to host isolation.
Exclusion count and age: number of exclusions, and those past their review date.
Silent hosts: endpoints with no telemetry for more than 24 hours.

Common failure patterns

EDR bought, nobody watching: high-severity alerts sit in the console over a weekend while ransomware (T1486) spreads.
Detect-only forever: prevention left in audit mode after the pilot, so the product records the attack it could have stopped.
Two active scanners: both products real-time scanning the same files, causing slowdowns, crashes and pressure to add broad exclusions.
Servers left on legacy antivirus: the endpoints attackers most want, such as domain controllers and hypervisor management hosts, have no EDR telemetry.
Tamper protection off: an attacker with local admin rights disables the agent or adds an exclusion before deploying tools.

Framework mapping

Framework	Reference	Antivirus	EDR
NIST SP 800-53 Rev. 5	SI-3 Malicious Code Protection	Primary	Supports
NIST SP 800-53 Rev. 5	SI-4 System Monitoring; IR-4 Incident Handling	Limited	Primary
NIST CSF 2.0	PR.PS-05 unauthorised software prevented	Primary	Supports
NIST CSF 2.0	DE.CM-09 computing and runtime monitored; RS.MI-01 incidents contained	Limited	Primary
CIS Controls v8.1	10.1 anti-malware deployed; 10.7 behaviour-based anti-malware	Primary	Primary for 10.7
MITRE ATT&CK	M1049 Antivirus/Antimalware	Primary	Includes
MITRE D3FEND	D3-PA Process Analysis	Partial	Primary

Practitioner checklist

Decide per platform whether you need antivirus, EDR, both, or allow-listing instead, and write down why.
Run exactly one active real-time scanner per endpoint and set coexistence modes before rollout.
Deploy EDR to servers and domain controllers first, not last.
Turn on tamper protection and alert on tampering attempts.
Move prevention from audit to block once the pilot is tuned.
Confirm someone answers high-severity alerts 24x7, in house or through MDR.
Treat EDR console roles and API clients as privileged identities.
Reconcile sensor coverage with the asset inventory every month.
Set telemetry retention to match your investigation and notification needs.

EDR vs Antivirus: What Changed and Whether You Still Need AV