CREST Penetration Testing vs CHECK: Which Is Right for Your Business in the UK

Introduction

Cyberattacks are increasing in sophistication and scale. In recent months, several high-profile data breaches have raised concerns among businesses across the UK. One growing challenge is the need to properly assess cybersecurity risks before attackers exploit them.

This blog is for business owners, IT professionals, government bodies, and cybersecurity teams who need to understand how to choose between CREST and CHECK penetration testing. If you are trying to secure sensitive data, protect your reputation, and stay compliant, understanding these frameworks is critical.

Understanding CREST and CHECK: What Are They?

One of the most common questions asked is whether a business needs a CREST-certified penetration test or a CHECK-approved one. These are both standards used in the UK for assessing penetration testing quality, but they apply to different environments and use cases.

CREST (Council for Registered Ethical Security Testers) is an international accreditation body that certifies companies and individuals who provide penetration testing, cyber incident response, and threat intelligence. It is often used by private companies looking to secure their networks through certified security assessments.

CHECK is the National Cyber Security Centre (NCSC) scheme designed for penetration testing services within government departments and Critical National Infrastructure (CNI). Only testers approved by NCSC under the CHECK scheme can perform these assessments.

To make this relatable, think of CREST like a certified driving instructor for the private sector, whereas CHECK is a police-accredited pursuit driver trained to handle high-risk situations in government environments. Both are experts, but they operate in different terrains.

This distinction matters now more than ever. As regulations tighten and threats evolve, businesses and government entities must ensure they are using the right penetration testing approach for their unique risk landscape.

Common Cybersecurity Threats That Penetration Testing Can Address

If you overlook penetration testing or use the wrong framework, the consequences can be severe. Common threats include:

• Ransomware Attacks: These can cripple operations and lead to data leaks. In 2024, ransomware accounted for over 25 percent of cyber incidents in the UK (NCSC Annual Review, 2024).
• Phishing and Social Engineering: Even secure systems can be compromised through staff manipulation. Penetration testing simulates these scenarios.
• Outdated Systems and Software: Unpatched vulnerabilities often go unnoticed without thorough testing.
• Supply Chain Attacks: A trusted third party may unknowingly introduce threats to your environment.

A real-world example includes the 2023 attack on a UK-based legal firm. It resulted in sensitive client data being stolen due to a misconfigured web application. A timely penetration test could have uncovered and mitigated the issue.

Ignoring penetration testing or using an uncertified provider may lead to a false sense of security, regulatory fines, and reputational damage.

Proactive Penetration Testing

To protect your organisation, proactive penetration testing is essential. Here are best practices to consider:

• Understand Your Environment: Identify whether your organisation falls under public sector requirements. If so, CHECK is likely required.
• Use Certified Testers: Always choose a CREST or CHECK-accredited testing provider. This ensures high standards.
• Adopt Recognised Frameworks: Align with NIST, Cyber Essentials, or ISO 27001 to integrate penetration testing into a broader security posture.
• Test Regularly: Perform annual or biannual tests and after major system changes.
• Fix Identified Issues Promptly: Testing is only effective if the vulnerabilities are addressed.

At Cybergen, we recommend businesses conduct a risk assessment first. Based on this, we advise whether CREST or CHECK penetration testing is needed. Our experts follow strict ethical guidelines, ensuring all engagements are secure, confidential, and constructive.

You can learn more about our approach to penetration testing here.

When CREST Is Sufficient

CREST is ideal for private sector businesses. Whether you operate an e-commerce store, a fintech startup, or a law firm, CREST-accredited testing gives you a reliable evaluation of your security posture.

CREST is also widely accepted in meeting the penetration testing requirement for the Cyber Essentials Plus certification. For most industries, CREST provides more than sufficient assurance that systems are secure.

CREST penetration testing is widely recognised in the cybersecurity industry for its rigour and consistency. It ensures that businesses receive professional, ethical, and standards-aligned assessments of their systems and infrastructure. CREST-accredited tests are suitable for organisations in the private sector looking to identify and remediate vulnerabilities before they are exploited by malicious actors.

Here Are The Key Areas Covered In A CREST Penetration Test

Web Applications

Web applications are often the most exposed parts of an organisation’s digital footprint. CREST testing identifies flaws such as SQL injection, cross-site scripting (XSS), insecure authentication, and session management weaknesses. These vulnerabilities can expose sensitive customer data or allow unauthorised access to internal systems.

Internal Networks

Internal penetration testing simulates the actions of a malicious insider or a compromised employee account. CREST testers assess how far an attacker could move laterally within your organisation’s network. They evaluate user permissions, shared drives, endpoint security, and the potential for privilege escalation.

External Infrastructure

This involves testing assets that are accessible from the internet, such as servers, firewalls, and routers. CREST-accredited testers examine the organisation’s perimeter to find misconfigurations, open ports, outdated services, and other common vulnerabilities that attackers frequently exploit to gain initial access.

Wireless Assessments

Wireless networks present unique challenges. Poorly secured wireless access points can be a gateway into your organisation’s network. CREST testing includes assessing encryption protocols, rogue access points, wireless segmentation, and device configurations to ensure wireless environments are secure.

By choosing a CREST-accredited testing provider, businesses ensure their security is evaluated by certified professionals using methodologies that meet industry and regulatory expectations. This not only reduces risk but also strengthens customer trust and compliance standing.

You can learn more about these services on our penetration testing page.



It is cost-effective, widely recognised, and often delivers quicker turnaround times than CHECK. Most importantly, it aligns with commercial risk tolerance and typical threat landscapes in the private sector.

When CHECK Is Mandatory

For organisations that work with or support the UK government, certain cybersecurity standards are not optional. The National Cyber Security Centre (NCSC) developed the CHECK scheme to ensure that sensitive public sector systems are tested by only the most rigorously assessed professionals. Understanding when CHECK is mandatory is essential for any organisation dealing with classified or sensitive government information.

CHECK penetration testing is not just an industry best practice. It is a formal requirement for government departments, agencies, and bodies responsible for delivering essential public services. This includes any organisation that handles, stores, or processes data classified as OFFICIAL or above.

CHECK accreditation ensures that penetration testing is carried out by individuals and companies who have been vetted and approved by the NCSC. These testers must meet strict criteria around security clearance, ethical conduct, and technical capability. This provides the government with confidence that assessments are being conducted by trusted professionals using approved methodologies.

CHECK testing is required or highly recommended in the following sectors:

Utilities

Energy and water providers form part of the UK's Critical National Infrastructure (CNI). A successful attack on one of these providers could have significant consequences for national safety and daily life. For this reason, NCSC mandates that these organisations use CHECK-certified testers when assessing cybersecurity resilience.

Telecommunications

Given the central role telecoms play in both government communications and public safety, they are subject to strict cybersecurity standards. CHECK testing helps ensure that any penetration test of core telecom infrastructure is carried out with confidentiality and national interest in mind.

Health Services

The NHS and related healthcare providers handle sensitive personal data and are increasingly digitised. A breach could disrupt care delivery or expose vast amounts of patient information. CHECK testing is crucial when systems are tied to national health strategies or classified operations.

Defence Contractors and Government Suppliers

Any private company working on classified contracts, military projects, or systems that feed into government services must use CHECK testers. These include aerospace firms, intelligence subcontractors, and suppliers who support operational continuity of government.

CHECK is also mandatory if your organisation must comply with specific regulatory frameworks such as:

• The Minimum Cyber Security Standard (MCSS): Introduced by the UK government, this outlines baseline cybersecurity controls for public sector organisations. Penetration testing under CHECK is often stipulated to demonstrate compliance.
• The Network and Information Systems (NIS) Directive: This applies to operators of essential services and digital service providers. It mandates rigorous cybersecurity measures, including testing through NCSC-accredited schemes.

One of the key benefits of CHECK is assurance. Because testers must hold high-level security clearance, organisations can trust that the testing will be conducted with integrity, confidentiality, and accountability. Moreover, the methodologies used by CHECK testers are aligned with the latest threat intelligence from NCSC, ensuring that assessments reflect the current threat landscape.

At Cybergen, we work with CHECK-certified professionals who understand both the technical and regulatory expectations for government-facing organisations. If your organisation is unsure about its obligations, our team can help you determine whether CHECK is necessary and guide you through the process.

Visit our penetration testing services to learn how we support public sector security with trusted, certified testing.

Choosing between CREST and Check 

Choosing between CREST and CHECK penetration testing is not just a matter of technical suitability; it also involves strategic planning around budget, timelines, and project goals.

Understanding the cost differences, project scope, and scheduling expectations can help your organisation make an informed and cost-effective decision.

Costs

The cost of penetration testing varies depending on several factors such as the size of the infrastructure, complexity of systems, depth of testing, and whether the engagement includes reporting and remediation advice.

CHECK testing generally comes at a higher cost. This is due to several contributing factors:

• Additional layers of security clearance and vetting for testers.
• The involvement of the National Cyber Security Centre (NCSC) for approvals and oversight.
• Extended and more thorough reporting standards aligned with government expectations.
• Often broader and deeper engagement to meet regulatory compliance, such as the Minimum Cyber Security Standard or NIS Directive.

In contrast, CREST testing is typically more cost-efficient. It offers flexible pricing that suits a range of budgets, particularly within the private sector. Companies that require penetration testing for internal risk management, Cyber Essentials Plus compliance, or ISO 27001 certification usually find CREST services offer strong value. While less expensive, CREST-accredited tests still meet stringent standards and can identify critical vulnerabilities that pose a threat to your systems.

At Cybergen, we work transparently with clients. We analyse the specific needs of your organisation and deliver a tailored quote. This ensures that you only pay for what is necessary, while still receiving industry-leading insight and service.

Scope

Scope is another critical consideration when comparing CREST and CHECK.

CHECK testing is tailored to high-risk, sensitive, or classified environments. It is mandatory for public sector bodies, government departments, and Critical National Infrastructure. The scope of CHECK projects often includes:

• Systems classified as OFFICIAL or higher
• Integration with national threat intelligence
• Highly sensitive data storage and processing environments
• Defence, energy, and telecommunications infrastructure

The CHECK methodology involves a deeper understanding of nation-state-level threats, geopolitical risks, and continuity planning. It is designed for environments where failure to secure systems could impact national safety or government operations.

CREST testing, on the other hand, offers broader flexibility across a wide range of industries. It is suited to:

• E-commerce platforms and online applications
• Financial service firms
• Professional service providers (legal, consulting, HR)
• Educational institutions
• Start-ups and SMEs
• Any private company seeking Cyber Essentials Plus or ISO 27001

CREST’s scope can be tailored precisely to a business’s digital footprint. It can include external infrastructure, web applications, cloud environments, and internal networks, without the added requirements of government-specific oversight.

Cybergen helps clients define the scope clearly and ensures no critical systems are overlooked during the testing engagement.

Turnaround Time

CHECK testing projects often involve more complex scheduling due to NCSC involvement. From initiating the engagement to final delivery, there may be longer lead times, especially during high-demand periods. This includes time required for project vetting, tester approvals, and final reporting aligned with government standards.

CREST testing typically benefits from a faster turnaround. Once scope and objectives are defined, testing can begin quickly. Reports are delivered efficiently, allowing for swift remediation actions and follow-up assessments if needed.

Businesses facing regulatory deadlines or rapid changes in infrastructure often favour CREST testing for its responsiveness and scalability.

At Cybergen, our process starts with a detailed discussion of your goals, compliance requirements, and technical architecture. From there, we provide a clear project plan, delivery schedule, and support throughout the engagement.

Visit our penetration testing services to learn more about how we manage testing projects for both private and public sector clients with precision, transparency, and efficiency.

The Cybergen Approach

Cybergen Security offers both CREST and CHECK penetration testing services. Our team of certified professionals works with clients across the UK to deliver insightful, actionable reports. We help organisations:

• Identify security weaknesses before attackers do
• Meet compliance requirements, including Cyber Essentials, ISO 27001, and NIS
• Build long-term resilience through continuous improvement

With Cybergen, you gain a partner who understands the UK regulatory landscape and modern threat environment. We empower clients through workshops, staff training, and customised advisory sessions.

Explore how our team can help you with penetration testing.

Summary

Understanding the difference between CREST and CHECK is crucial to making the right choice for your organisation. CREST is best for the private sector and offers flexible, fast, and cost-effective testing. CHECK is required for government departments and critical infrastructure, offering a higher level of assurance.

Ignoring this choice could leave your organisation exposed. Cybergen is here to guide you through this process, offering expert advice and accredited testing services.

Get in touch with Cybergen today to assess your needs and secure your future.

Ready to strengthen your security posture? Contact us today for more information on protecting your business.