Endpoint Detection and Response (EDR) for UK Businesses

What Is Endpoint Detection and Response?

Endpoint Detection and Response (EDR) is a category of cybersecurity software that continuously monitors device activity to detect, investigate, and respond to threats in real time. Unlike traditional antivirus, which compares files against a database of known malware signatures, EDR analyses behaviour — monitoring how processes interact with the operating system, file system, memory, and network. For UK businesses facing an increasingly hostile threat landscape, EDR represents a fundamental upgrade in endpoint protection capability.

The scale of the problem is significant. According to the DSIT Cyber Security Breaches Survey 2025, 43% of UK businesses experienced a cybersecurity breach or attack in the past twelve months. Many of these attacks used techniques — fileless malware, credential theft, living-off-the-land binaries — that traditional signature-based antivirus simply cannot detect. EDR addresses this gap by focusing on what software does rather than what it looks like, making it effective against both known and novel threats.

This behavioural approach allows EDR to detect novel threats, including malware variants that have been modified to evade signature detection, fileless malware that operates entirely in memory, and living-off-the-land attacks that abuse legitimate system tools like PowerShell or WMI to carry out malicious activity. For businesses exploring broader endpoint protection strategies, our guide to endpoint detection and response covers the full landscape.

How EDR Works: The Detection and Response Cycle

An EDR agent installed on each endpoint continuously captures telemetry — process events, file system changes, registry modifications, network connections, and memory operations. This telemetry is sent to a central platform (typically cloud-based for modern solutions) where it is analysed against detection rules, threat intelligence feeds, and machine learning models trained on millions of known attack patterns.

The detection process operates in several layers. First, known indicators of compromise (IOCs) — malicious file hashes, command-and-control server addresses, known exploit signatures — are matched against incoming telemetry. Second, behavioural analytics identify suspicious patterns: an Office document spawning a PowerShell process that then makes a network connection to an unusual external address, or a process rapidly encrypting files across multiple directories. Third, machine learning models trained on legitimate versus malicious behaviour flag anomalies that rule-based detection might miss.

When suspicious behaviour is identified, the EDR platform generates an alert and can take automated response actions depending on configuration and confidence level. These response actions include quarantining a file, terminating a malicious process, isolating the compromised device from the network to prevent lateral movement, or rolling back changes made by ransomware. This combination of detection and automated response significantly reduces the time between threat identification and containment — a critical factor in ransomware scenarios where every minute of delay allows encryption to spread to additional files and devices.

EDR platforms also retain historical telemetry data, enabling security analysts to investigate incidents retrospectively. When a threat is discovered, analysts can trace the full attack chain — from initial compromise through lateral movement to data access — using the recorded telemetry. This forensic capability is essential for understanding the scope of an incident and for strengthening defences against similar future attacks.

EDR vs Traditional Antivirus: Why Signatures Are No Longer Enough

Traditional antivirus protects against threats it has already seen — known malware that has been catalogued and added to a signature database. It is effective against commodity threats but struggles fundamentally with novel variants, polymorphic malware that changes its signature on each infection, and fileless attacks that leave no files to scan. The gap between what antivirus can detect and what modern attackers deploy has widened substantially over the past five years.

EDR addresses these gaps by focusing on activity rather than appearance. A piece of ransomware that has never been seen before will still trigger EDR detection when it begins encrypting files, because the pattern of rapid file modification across multiple directories is anomalous behaviour regardless of the specific malware involved. Similarly, a fileless attack that uses PowerShell to download and execute malicious code in memory — leaving no file for antivirus to scan — is detected by EDR because the process behaviour is suspicious.

For UK businesses considering endpoint protection options, the choice between antivirus and EDR is no longer a matter of preference. The average cost of a data breach for UK organisations was £3.4 million according to IBM's 2024 Cost of a Data Breach report. Against threats of this magnitude, relying solely on signature-based detection is an inadequate defence. Our comparison of managed antivirus solutions explains how modern endpoint protection has evolved beyond traditional approaches.

What EDR Detects That Antivirus Cannot

Understanding the specific threat categories that EDR addresses helps clarify why the technology matters for UK businesses:

• Fileless malware — Attacks that operate entirely in memory without writing files to disc. These attacks use legitimate system tools (PowerShell, WMI, .NET) to execute malicious code, leaving no file for traditional antivirus to scan.
• Living-off-the-land attacks — Techniques that abuse legitimate, pre-installed system tools to carry out malicious activity. Because the tools themselves are legitimate, signature-based detection cannot flag them; only behavioural analysis of how they are being used reveals the threat.
• Credential theft and lateral movement — Attacks that harvest credentials from memory (using tools like Mimikatz) and then move laterally through the network using those stolen credentials. EDR detects the suspicious process behaviour associated with credential dumping.
• Zero-day exploits — Attacks exploiting vulnerabilities that have not yet been patched or publicly disclosed. Since no signature exists, EDR's behavioural detection is the primary defence layer.
• Ransomware variants — New ransomware strains are created daily, making signature databases perpetually incomplete. EDR detects the encryption behaviour pattern regardless of the specific ransomware family involved.

Microsoft Defender for Business as EDR

For most UK SMEs, Microsoft Defender for Business is AMVIA's primary EDR platform. It is included in Microsoft 365 Business Premium at no additional licence cost and provides genuine EDR capability: behavioural detection, attack surface reduction rules, endpoint isolation capability, and integration with Microsoft's global threat intelligence network. Defender for Business is significantly more capable than the consumer Windows Defender built into Windows 10 and 11 — it includes cloud-delivered protection, automated investigation capability, and integration with the broader Microsoft 365 Defender security suite.

AMVIA configures Defender for Business to Microsoft's recommended security baseline, enables attack surface reduction rules targeting common attack techniques (blocking Office applications from creating child processes, preventing credential stealing from the Windows local security authority subsystem, and blocking untrusted processes from running from USB drives), and integrates endpoint alerts with AmviaIQ for continuous monitoring and investigation.

Attack surface reduction (ASR) rules deserve particular attention. These rules prevent specific attack techniques from executing in the first place — blocking the attack before EDR detection is even needed. For example, an ASR rule can prevent Office macros from making Win32 API calls, eliminating a common initial access technique used by phishing campaigns. Properly configured ASR rules substantially reduce the volume of threats that EDR needs to detect and contain.

When Huntress EDR Adds Value

For businesses requiring a higher tier of managed detection — those in regulated sectors, those with elevated risk profiles, or those seeking MDR-level coverage — AMVIA deploys Huntress EDR alongside or instead of Defender for Business. Huntress adds a managed analyst layer that investigates every endpoint alert, reducing noise and ensuring genuine threats receive expert human analysis within minutes rather than hours.

Huntress is purpose-built for the SME and managed service provider environment. Its analysts review every suspicious detection, provide clear remediation guidance, and can take direct containment action when a confirmed threat is identified. This human-in-the-loop approach is highly effective at detecting persistent threats — such as backdoors and remote access trojans — that automated tools can miss because they mimic legitimate remote access software.

Deploying EDR: What UK Businesses Should Expect

EDR deployment for a typical UK SME involves several stages. First, the EDR agent is deployed to all managed endpoints — laptops, desktops, and servers. For businesses using Microsoft 365 Business Premium, Defender for Business deployment is managed through Microsoft Intune and can be completed without physical access to devices. Second, detection policies and attack surface reduction rules are configured according to the business's risk profile and operational requirements. Third, alert monitoring and investigation processes are established — either in-house or through a managed service.

The cost context for EDR varies by approach. Microsoft Defender for Business is included in M365 Business Premium (approximately £19.70 per user per month), making it effectively free for businesses already on that licence tier. Huntress EDR is priced per endpoint per month, with costs varying based on volume. Only 14% of UK businesses have a formal incident response plan (DSIT Cyber Security Breaches Survey 2025), which means many businesses deploying EDR will also need to establish response procedures to ensure detections lead to action rather than accumulating in an unmonitored dashboard.

Key Considerations for UK SMEs

• EDR alerts require human investigation — without a managed service, alerts may accumulate without being acted on, providing no security benefit despite the technology being deployed
• Microsoft Defender for Business provides EDR capability for businesses on M365 Business Premium at no additional licence cost — making cost a poor reason not to deploy EDR
• Attack surface reduction rules should be configured alongside EDR — they prevent many attacks before detection is needed, reducing alert volume and improving security posture
• EDR should cover all managed endpoints — laptops, desktops, and servers — without exception; a single unprotected device can be the entry point for an attack that affects the entire organisation
• Ensure EDR is integrated with your incident response process so detections trigger a defined response, not just an email notification that may be ignored
• Cyber Essentials certification requires malware protection on all devices — EDR satisfies this control and provides substantially stronger protection than basic antivirus

How AMVIA Can Help

AMVIA deploys and manages EDR for UK SMEs as part of its managed cybersecurity service. We configure Microsoft Defender for Business or Huntress EDR, deploy attack surface reduction rules, monitor alerts through AmviaIQ, investigate significant detections, and take containment action when threats are confirmed. Monthly reports provide visibility of protection status and any incidents across your managed endpoint estate.

For businesses currently relying on traditional antivirus, AMVIA provides a structured migration path to EDR — assessing the current endpoint estate, deploying EDR agents, configuring detection policies, and establishing monitoring procedures. The transition is managed with minimal disruption to day-to-day operations. Call AMVIA on 0333 733 8050 to discuss EDR requirements for your business.