Adopting the NCSC CAF 4.0: Detecting and Responding to Cyber Security Events
Part 2 of a 2-part series on adopting the NCSC Cyber Assessment Framework (CAF 4.0)
The NCSC Cyber Assessment Framework (CAF 4.0), released in September 2025, reinforces the need for organisations to move from reactive cyber security practices to measurable, outcome-based resilience. It guides how essential functions can be protected, monitored, and restored if disruption occurs.
Following on from our earlier discussion on Objective A: Managing Security Risk, this article focuses on Objectives C and D, which address two critical capabilities: detecting cyber security events and minimising their impact. Those seeking a discussion of Objective B should refer directly to the NCSC CAF 4.0 document which defines the management of the policies, process and procedures necessary to protect the network and information systems supporting essential functions.
Together, these objectives recognise that no matter how mature an organisation’s controls are, security incidents will still happen. The key to resilience lies in detecting them early, responding effectively, and recovering swiftly.
Objective C – Detecting Cyber Security Events
Outcome
The organisation should maintain security monitoring and threat hunting capabilities to detect and analyse incidents that could affect essential functions.
Objective C emphasises the need for continuous monitoring, timely detection, and accurate analysis of cyber security events. Organisations must ensure their monitoring practices are both technically effective and regularly reviewed for relevance, accuracy, and performance.
Security Monitoring
Monitoring the security status of networks and systems supporting essential functions is central to this objective. Effective monitoring requires the comprehensive collection and analysis of event data, not only from security tools, but also from applications, infrastructure, and user activity.
Logs must be collected, analysed, and retained securely. They should be protected against tampering, accessible only to authorised personnel, and enriched with timely contextual data to support accurate incident triage. Regular reviews ensure that correlation rules and alert thresholds remain tuned to evolving threats.
Modern security operations depend on near real-time visibility. Continuous telemetry collection allows organisations to identify anomalies as they occur, enabling proactive rather than reactive responses. The CAF stresses that this capability must be both systematic and evidence-based and that every alert should link back to measurable processes and outcomes.
People, Skills and Automation
CAF 4.0 recognises that effective monitoring and threat hunting depend as much on people as on technology. Skilled analysts must interpret vast amounts of telemetry, distinguish false positives from real threats, and coordinate responses under pressure.
However, this dependence can introduce a potential point of failure. Human fatigue and information overload can compromise detection quality. Automation, guided by well-designed playbooks and integrated workflows, will increasingly help analysts overcome these challenges. Streamlined processes, supported by data-driven tools, ensure analysts can focus their expertise where it matters most.
Threat Hunting
While traditional monitoring focuses on reactive detection, threat hunting takes a proactive approach. It involves systematically searching for signs of malicious activity that may have evaded existing defences or failed to trigger alerts.
Threat hunting relies on current threat intelligence, behavioural analysis, and deep familiarity with “normal” user and system operations. Analysts should look for subtle deviations or indicators of compromise that suggest adversarial activity.
Regular threat hunting exercises not only improve detection performance but also strengthen the overall cyber security posture. They identify emerging vulnerabilities before they can be exploited and provide valuable feedback to refine automated monitoring processes.
Objective D – Minimising the Impact of Cyber Security Incidents
Outcome
Capabilities exist to minimise any adverse impact of a cyber security incident on the operation of essential functions, including their re-establishment if necessary.
Even the most sophisticated defences cannot guarantee immunity from attack. Objective D recognises this reality, focusing on how organisations prepare for and respond to incidents when they occur.
The goal is not just to contain the immediate damage but to preserve business continuity, protect essential services, and learn from every event.
Incident Response and Recovery
An effective incident response plan is the foundation of operational resilience. It should be current, tested, and aligned with the organisation’s risk profile and business priorities. The plan must define roles, responsibilities, and escalation paths while integrating seamlessly with wider business continuity and disaster recovery frameworks.
When an incident occurs, teams need access to accurate, timely information, including details of unmitigated vulnerabilities, affected assets, and previous incident patterns. This intelligence allows for faster decision-making and targeted remediation.
Recovery capabilities must also be clearly defined. Backup systems, alternate environments, and manual workarounds should be tested regularly to ensure essential functions can be re-established quickly.
Lessons Learned and Continuous Improvement
The CAF encourages organisations to treat each incident, real or simulated, as a learning opportunity. Post-incident reviews should assess not only what went wrong, but also how detection, communication, and decision-making can be improved.
This cyclical process of review and refinement helps maintain readiness. It embeds cyber security response as a living discipline, continually adapting to emerging threats, evolving technologies, and shifting organisational priorities.
How Huntsman Security Supports CAF Objectives C & D
The CAF’s outcome-based approach demands measurable assurance and performance improvement. Huntsman Security provides the visibility, automation, and analytics capabilities organisations need to detect, respond, and recover effectively from cyber security incidents.
- Huntsman Enterprise SIEM delivers comprehensive, near real-time monitoring and alerting. It ingests and correlates event data from across the enterprise, enabling timely detection of anomalies and threats. Its flexible architecture supports secure log management, data enrichment, and configurable workflows that align to organisational policies and response procedures.
- Integrated playbooks and automation streamline triage and incident response, reducing analyst workload while maintaining high accuracy and repeatability.
- Threat hunting support within the SIEM allows analysts to query vast volumes of telemetry and identify behaviours that traditional rules might miss.
- Huntsman Scorecard complements these capabilities by providing continuous, evidence-based measurement of the state of control effectiveness, enabling boards and governance stakeholders to assess readiness and resilience objectively.
Together, these technologies transform cyber operations from reactive monitoring to proactive resilience, directly supporting the CAF’s intent for measurable, outcome-driven security management.
From Detection to Resilience
Objectives C and D of the NCSC CAF 4.0 capture the essence of modern cyber security: anticipate, detect, respond, and recover. They remind organisations that resilience is not achieved through technology alone, but through the seamless integration of people, processes, and data-driven assurance.
By adopting the CAF’s outcome-based model, and enabling it with continuous monitoring, automated analysis, and actionable intelligence, organisations can ensure that when incidents occur, they are managed swiftly and effectively, with minimal disruption to essential functions.
Huntsman Security’s Enterprise SIEM, Scorecard, and SmartCheck solutions enable that continuous assurance, helping organisations demonstrate CAF compliance while achieving true, sustainable cyber resilience.
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