Full Report
Our view of good cyber adversary simulation – and how assured providers can deliver it.
Analysis Summary
# Best Practices: Cyber Adversary Simulation (CyAS)
## Overview
Cyber adversary simulation systematically and safely tests an organization's security posture by mimicking real-world cyber attackers. These practices help organizations evaluate their capability to prevent, detect, and respond to threats. Rather than acting as a simple pass/fail exercise, effective adversary simulation provides a capability-led assessment of threat identification, triage speed, and escalation protocols.
## Key Recommendations
### Immediate Actions
1. **Download and Review Guidelines:** Access the National Cyber Security Centre (NCSC) "Adversary Simulation: What You Need to Know" guidance and initial CyAS scheme documents.
2. **Assess Organization Maturity:** Determine if your organization has sufficiently mature cybersecurity processes and technologies to benefit from an adversary simulation, as it is not intended for baseline environments.
3. **Engage Stakeholders:** Share the newly published NCSC Scheme Standard and Working Practices Document (WPD) with internal security teams, procurement officers, and relevant business leaders to align expectations.
### Short-term Improvements (1-3 months)
1. **Refine Procurement Standards:** Update vendor procurement documentation to align with the NCSC CyAS Core Standard benchmarks. Ensure providers use a capability-led approach rather than executing fixed scripts.
2. **Establish Safe Scoping Processes:** Define strict operational parameters for testing live services and sensitive systems to minimize business disruption risks during simulations.
3. **Formulate Bespoke Objectives:** Move away from standard "tick-box" testing methodologies. Collaborate with internal threat intelligence teams to outline specific, tailored simulation objectives based on actual sector threats.
### Long-term Strategy (3+ months)
1. **Transition to Assured Providers:** Prepare to transition adversary simulation contracts to NCSC-assured CyAS providers following the formal scheme launch (targeted for November 2026).
2. **Integrate Regulatory Requirements:** Work alongside sector-specific oversight bodies and regulators to layer specialized compliance mandates on top of the core CyAS standard.
3. **Continuous Feedback Loop:** Embed simulation outcomes directly into the organization's risk management lifecycle, ensuring insights regarding gaps in threat identification, triage, and escalation drive future capital investments.
## Implementation Guidance
### For Small Organizations
- Focus first on foundational security practices such as the NCSC "Cyber Essentials" framework.
- Utilize specialized lower-maturity programs, such as the NCSC "Cyber Advisor" scheme, before attempting a full adversary simulation.
### For Medium Organizations
- Evaluate current internal detection capabilities to ensure there are mature logging and monitoring processes worth testing.
- Use the NCSC CyAS Scheme Standard as a self-assessment checklist to evaluate existing third-party penetration testing or red-teaming providers.
### For Large Enterprises
- Adopt the CyAS approach entirely by requiring providers to leverage continuous reconnaissance and bespoke adversarial mindsets rather than replaying static lists of known attacker behaviors.
- Ensure that simulations involve multi-tiered response testing, specifically tracking how effectively internal Security Operations Centers (SOCs) escalate incidents to leadership.
## Configuration Examples
*Note: The NCSC CyAS scheme documents do not provide specific command-line technical configurations. Instead, they outline structural requirements for executing tests:*
- **Strategic Approach:** Shift from static, playbook-driven attack scripts to dynamic, threat-intelligence-led scenarios.
- **Operational Requirement:** Simulations must incorporate a customized reconnaissance phase executed by the provider to identify organizational weaknesses organically, rather than relying on pre-disclosed network paths.
## Compliance Alignment
- **NCSC Cyber Assessment Framework (CAF):** Aligning simulation objectives directly supports compliance metrics within the CAF.
- **NCSC CyAS Scheme Standard:** Provides a transparent and consistent benchmark used by oversight bodies and government policy organizations to judge sector-wide cyber resilience.
## Common Pitfalls to Avoid
- **Treating Simulations as a Tick-Box Exercise:** Relying on basic pass/fail criteria instead of extracting detailed telemetry data regarding response weaknesses.
- **Utilizing Fixed Attack Scripts:** Hiring providers who simply replay static, known attacker playbooks instead of simulating an adaptable, persistent adversarial mindset.
- **Uncontrolled Live Testing:** Poorly defining or managing simulation parameters, which can result in unintended downtime for critical or sensitive systems.
## Resources
- **NCSC Adversary Simulation Guidance:** hxxps[://]www[.]ncsc[.]gov[.]uk/guidance/adversary-simulation-what-you-need-to-know
- **CyAS Scheme Documents Hub:** hxxps[://]www[.]ncsc[.]gov[.]uk/schemes/cyber-adversary-simulation-cyas/introduction/cyas-scheme-documents
- **CyAS Scheme Core Standard:** hxxps[://]www[.]ncsc[.]gov[.]uk/schemes/cyber-adversary-simulation-cyas/introduction/cyas-scheme-documents/cyas-standard
- **Working Practices Document (WPD):** hxxps[://]www[.]ncsc[.]gov[.]uk/schemes/cyber-adversary-simulation-cyas/introduction/cyas-scheme-documents/cyas-wpd
- **NCSC Cyber Assessment Framework (CAF):** hxxps[://]www[.]ncsc[.]gov[.]uk/section/advice-guidance/all-topics/cyber-assessment-framework