We find the vulnerabilities other testers can’t.
Penetration Testing Services
Work with some of the most distinguished and highly accredited Penetration Testers in the UK. Risk-assess every system and scenario, from your public facing digital footprint to the people and networks that keep you online.
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1800+
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Penetration Tests completed since the start.
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220+
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Penetration Testing customers.
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20+
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Consultants in-house maintaining our high standards.
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10+
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Years as a trusted, certified CREST member.
Why Trustmarque?
Trustmarque have a dedicated team of carefully selected cyber experts. With over 20 CHECK and CREST-certified testers, many holding DV and NPPV3 security clearances, the team delivers consultant-led assessments tailored to each client’s unique environment. Trustmarque’s rigorous quality assurance ensures that every report is independently reviewed and delivered within five working days, offering actionable insights and remediation plans that empower organisations to fix vulnerabilities before attackers find them.
Why do organisations choose Penetration Testing services from Trustmarque?
We continuously adapt our Penetration Testing capabilities, ensuring we can realistically simulate the attack chains used by criminals in a cloud-based, AI-driven world. By providing comprehensive, contextual reports, we help you define and prioritise the best course of remediation, acting quickly and meaningfully.
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36+
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Years of experience
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As a managed service provider, building tight relationships with vendors across the security industry.
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40%
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Team growth year on year since 2019
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Highlighting our dedication to keeping up with our customers’ needs.
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115%
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Cyber practice growth in 2025 alone
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Demonstrating how the results we provide contribute to lasting customer trust.
Our Penetration Testing Services
Our comprehensive portfolio spans a wide range of technologies and business use cases. Designed to support the natural cadence of your Penetration Testing programme, it enables you to meet mandated, compliance‑driven testing requirements while addressing your inevitable ad-hoc and sometimes unexpected testing needs.
Network Penetration Testing
We perform objective-based security assessments of your internet-facing services and internal networks.
Web Application Penetration Testing
Expose exploitable flaws within user-facing functionality — application logic, authentication, sessions, and inputs — using the OWASP Top 10.
Web Service Testing
Uncover backend weaknesses in APIs and services, including authentication, authorisation, and data handling beyond the browser.
Server Build Review
We evaluate your server’s build and configuration to identify performance, security, and reliability risks from an operational standpoint.
Client Security Evaluation
We evaluate employee workstations, including desktops and laptops, against security best practices and industry standards to identify potential vulnerabilities.
Breakout Testing
We assess the configuration and security posture of your user environment from an authenticated perspective to identify risks accessible to legitimate users.
Network Device Security Review
We perform a comprehensive configuration review of network devices such as firewalls, routers, and switches to identify misconfigurations and security gaps.
Network Segregation Testing
We verify that your network controls effectively restrict traffic according to security policies and requirements.
Wireless Penetration Testing
We evaluate whether an attacker could gain access to your network and escalate their reach beyond initial entry points.
Social Engineering
We assess the security awareness of your personnel and the effectiveness of your processes through targeted testing and simulations.
Red Team Operations
We simulate real-world cyber attacks to identify and address vulnerabilities before actors can exploit them.
Bespoke Testing Services
Tailored security assessments shaped around your specific business needs, infrastructure, and risk profile.
Download our Penetration Testing brochure to learn more about our services
This engagement has been one of the best – if not the best – engagement I’ve experienced with a Pen Test company whilst at Agiito. The testers were a real credit to Trustmarque - everyone was.
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98%
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Were happy with our Penetration Testing services
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97%
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Would recommend us as a provider
Accreditation & Certification
We’re the only Penetration Testing company in the UK holding both NCSC CHECK and all 6 Microsoft Solution partner designations. This achievement demonstrates our commitment to delivering the highest standards of security testing while maintaining expertise across the vendor systems our customers rely on.
We’ve been a CREST member for over 10 years and continue to invest in the certification of our team, many of whom are already some of the most highly certified practitioners in the country.
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CRT
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CCT INF
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CCT APP
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CPSA
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CSTM
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CSTL-INF
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CSTL-APP
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ChCSP
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PriCSP
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PraCSP
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OSCP
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CRTO
Public Sector Expertise
We deliver Penetration Testing services for public sector bodies, the police, NHS, and government projects. By maintaining the necessary levels of security clearance in-house, we ensure our team can consistently deliver services that are compliant, governance-led, and which safeguard highly sensitive information. We already serve many public sector customers, providing a range of regulated solutions from CHECK to HSCN (Health and Social Care Network) readiness testing.
Why Penetration Testing?
Penetration Testing remains a crucial part of the cyber security mix. Threat actors, technologies, and organisations are changing and evolving all the time, making it essential to maintain control of the risks emerging daily across your attack surface.
Test AI attack paths
Validate whether AI services and automations are introducing new vectors to bypass controls or expose sensitive data.
Quantify real-world impact
Understand your true exposure to real-world attacks, revealing risk across your attack surface.
Meet compliance obligations
Respond to PCI-DSS, DORA, GDPR, ISO 27001, and other industry requirements.
Validate supply-chain risk
Assess how partners, vendors, and services expand your attack surface and expose inherited risk.
Trustmarque offered excellent customer service and superb testing quality and consistency. Vulnerabilities have been unearthed that went unnoticed with some of our previous testing providers. I would always recommend Trustmarque, especially considering the quality I received from other testing companies. I wholly look forward to continuing working alongside the team in the years to come.
What to expect from your Penetration Test
Simple setup, thorough execution. Our penetration testing process takes you from initial request to clear, actionable results, with expert support throughout.
Request: Start Your Assessment
Begin your assessment by sharing a few details about your systems, goals, and security concerns so we can shape the right testing approach for your needs.
Scoping & Proposal: Define Your Testing Objectives
Connect with a senior cybersecurity consultant to define project scope, priorities, timelines, and compliance requirements, designing a test that's aligned with your needs.
Pre-test: Authorisation and Access
We confirm authorisation, system access and communication plans, so you know what will be tested, when, and by whom.
Testing Phase: Simulating Real-World Cyberattacks
Our consultants run controlled penetration tests using real-world techniques, providing updates and instant alerts for any critical security risks.
Wash-up call: Reviewing Initial Findings
We walk you through key findings, your current security posture, and priority vulnerabilities before you receive the final report.
Results & Report: Clear, Actionable Insights
You receive a comprehensive penetration testing report detailing vulnerabilities, business impact, and practical remediation guidance.
Post-Engagement Meeting: Strengthen Your Security Posture
Review the test results, discuss how Trustmarque can support future risk reduction and plan ongoing cybersecurity improvements.
Penetration Testing FAQs
Do you use AI and automation in your penetration testing services?
How do your penetration testing services help my overall cyber resilience?
Cyber resilience is an organisation’s ability to anticipate, withstand, recover from, and adapt to adverse cyber events, utilising a mixture of clear governance, prepared people, proven processes, and actively managed security controls to do so.
Penetration testing is a key part of the security mix needed to achieve cyber resilience. As per the NCSC’s Cyber Assessment Framework (CAF) organisations must be able to:
- Manage security risk
- Protect themselves against attacks
- Detect cyber security events
- Minimise the impact of incidents
Penetration testing primarily features in the NCSC Cyber Assessment Framework (CAF) under Objective B: Protecting against cyber attack (specifically Principle B4: System Security), as a means to ‘prevent the exploitation of known vulnerabilities in networks and information systems’.
It also falls under the category of managing cyber risk, as it can be used to identify risks and gain assurance by providing evidence of the security in your systems and processes.
How do you maintain high standards of penetration testing?
I found communication with Trustmarque to be first-class from initiation to completion, as has been the case in previous years using their penetration testing services.