PENETRATION TESTING SERVICES

CREST-certified penetration testing services, delivered by UK-based experts, tailored to your business needs.

Trusted by leading organisations

Wise, a financial technology company
Jojo Maman Bebe, a baby clothing retailer and part of Next Plc
Pluxee, a Software as a Service (SaaS) company and part of Sodexo
Block, an IT Managed Services company
StoreFeeder, an e-commerce company and part of the Royal Mail Group
Unicard
Plus Company
Kyloe Partners, a recruitment technology company

We help organisations uncover the real risks lurking in their environments. Our penetration testing services go beyond checklists, providing meaningful testing with maximum coverage.

Whether you’re looking to meet compliance, build trust with customers, or strengthen your security posture, Sentrium gives you the insight you need to move forward with confidence.

  • UK-based CREST-certified testers
  • Fast turnaround and clear communication
  • Tailored tests based on your needs and risk profile

We work with UK organisations of all sizes, from funded startups to public sector, who need quality testing without disruption.

Why should you work with Sentrium?

Discover critical vulnerabilities
before attackers do

Get CREST-certified penetration testing from UK-based experts to protect your technology and data with comprehensive, business-tailored security testing.

Request a quote

Penetration testing (or pentesting) involves finding and exploiting vulnerabilities within your IT systems, websites, applications and cloud infrastructure. It’s sometimes referred to as ‘ethical hacking’. Penetration testers find methods attackers use to gain access to your assets.

Trusting the effectiveness of your organisation’s IT security controls is crucial to mitigating risks and preventing malicious access to your systems and data. Pentesting enables you to remediate vulnerabilities and improve your organisation’s security strategy.

What is penetration testing
Why does your organisation need a pentest?
  • Gain assurance in your IT security controls’ effectiveness
  • Prevent malicious actors from accessing or making changes to your systems and data
  • Maintain compliance with data regulations to protect personally identifiable information (PII) within your IT environment
  • Prevent data breaches or loss
  • Prove to customers or other stakeholders (i.e., during a business acquisition) that products, services or internal security practices are appropriate to protect their interests

Our consultants conduct rigorous penetration testing of your networks, systems and applications using industry-standard practices. We are CREST-approved and certified to the UK penetration testing discipline. Each of our pentesting services adheres to the following assessment methodology:

Penetration testing reconnaissance

Reconnaissance

Pentesting starts with mapping the target environment, system or application to establish the avenues of attack. We obtain detailed information about the attack surface using active and passive information gathering.

Penetration testing fingerprinting

Fingerprinting

We perform further scanning to find details about your assets. This process often reveals versions of software, exposed sensitive files, misconfigured services and other facts that require further investigation.

Penetration testing analysis

Analysis

With a vast amount of information gathered about the target(s), we combine manual and automated techniques to find attack vectors. Our expertise allows us to discover vulnerabilities and demonstrate exploitation.

Penetration testing exploitation

Exploitation

We use our advanced technical capability and a mix of tools, scripts and offensive techniques to simulate the exploitation of vulnerabilities. We’ll communicate with you before we start to ensure you’re happy for us to continue.

Penetration testing lateral movement

Lateral Movement

Once we’ve achieved a foothold via successful exploitation, our team replicates the attack lifecycle to find and compromise other targets of value within the context of exploited systems.

Penetration testing cleanup

Cleanup

Once we’ve obtained evidence of the successful attack chain, we remove any artefacts or changes applied to the system, restoring it as closely as possible to its original state.

Start protecting what matters
most to you

We tailor every engagement to your environment and goals.
Start with a quick call to discuss what you need, no hard sell, just assurance.

Book your pentest

Every penetration testing engagement includes a concise, well-structured report designed to help you understand and address the risks identified. You’ll receive:

  • A clear summary for stakeholders, highlighting key risks and priorities
  • Full technical details of each vulnerability, including severity ratings
  • Practical step-by-step remediation guidance
  • Screenshots and reproduction steps where necessary
  • A free retesting window to validate fixes

Our consultants are available to walk you through the findings and answer any follow-up questions, helping you turn insight into action.

Penetration testing reporting

Penetration testing is a broad term covering several types of offensive cyber security assessment. Our team provides the following penetration testing services:

Penetration testing services

Network penetration testing

Our testing simulates attacks on your internal and external networks to expose misconfigurations, outdated systems, and other exploitable weaknesses.

Website penetration testing

Website penetration testing

We identify vulnerabilities in websites, portals, and APIs, from OWASP risks to logic flaws, helping you secure your online assets and meet compliance requirements.

Mobile penetration testing

Mobile application penetration testing

We test iOS and Android apps for security flaws in both the app and backend APIs, uncovering issues like insecure storage and weak authentication.

Cloud penetration testing

Cloud penetration testing

We identify cloud-specific misconfigurations and vulnerabilities across platforms like AWS, Azure, and GCP, ensuring your setup is resilient and secure.

Vulnerability Assessment

Vulnerability assessment

A cost-effective way to find known vulnerabilities using automated scans and expert review, ideal for prioritising fixes and improving security posture.

Red teaming

Red teaming

A realistic attack simulation that tests your organisation’s defences, combining social engineering, stealth tactics, and advanced intrusion techniques.

Common vulnerabilities

Despite growing awareness and understanding of cyber security in all aspects of business, common vulnerabilities and weaknesses still affect many applications, networks and services. Sentrium’s CREST-approved penetration testing services help identify and remediate these vulnerabilities, enabling organisations to protect assets that malicious actors may target. Our penetration tests often find vulnerabilities such as:

Insecure configurations

Systems, applications, software packages and cloud environments can be highly configurable. Misconfigured features can have a disastrous effect on a service’s overall security posture.  

Outdated and vulnerable software

Patching may be a basic security principle, but the reality can be incredibly complex. Discovering outdated and unsupported software during a penetration test is not unusual. Unsupported software no longer receives security patches and is commonly targeted by opportunistic attackers.  

Business logic flaws

Incorrect assumptions about how users will interact with a system can result in logic flaw vulnerabilities. In web applications, this is often seen in excessive reliance on client-side controls, which allow the malicious manipulation of workflows.  

Insecure programming practices

Common weaknesses include injection vulnerabilities, such as command injection, database (SQL) injection and cross-site scripting (XSS). These vulnerabilities often seriously affect an application’s security and the sensitive data it processes.  

Cryptographic failures

Cryptographic failures include the improper use of unsecured protocols, ciphers, certificates and legacy encryption technologies. These weaknesses may allow a hacker to intercept sensitive information as it moves across a network. 

Frequently asked questions

What are penetration testing services?

Penetration testing services involve the assessment of an organisation’s systems, networks, or applications using techniques and tools similar to those used by malicious actors. This process identifies security vulnerabilities and provide insights to help organisations understand and reduce their cyber risk.

How often should a penetration test be performed?

Penetration testing should be done annually at minimum, or more often if you deploy new systems, update applications frequently, or need to meet regulatory standards.

How long does a penetration test take?

A penetration test can take between 1 to 6 weeks. This depends on the project’s scope and complexity. For example, the size of the network under review, the type of network, and whether any pentesting is performed authenticated may affect the length of the assessment.

Will a pentest disrupt our services?

Our skilled pentesters follow strict guidelines and legal and technical standards to ensure minimal disruption to your business. Our consultants work with you to establish high-risk systems and operational concerns during the scoping process.

Is Sentrium a CREST-approved provider?

Yes! Sentrium has achieved the standards set by CREST and is a CREST-approved penetration testing service provider. We’re proud to offer services that achieve CREST’s extremely high standards of quality and professionalism, which are recognised internationally.

What happens after a penetration test?

Once your penetration test is complete, we compile a detailed report containing the identified vulnerabilities, what risks they pose and recommendations on how to remediate them. Once we’ve delivered the report, our team will be available to discuss the results in detail and answer any questions.

What steps are involved in a penetration test?

Once we’ve established the scope of the assessment, our CREST-accredited team provides penetration testing services using an industry-standard methodology. First, a pentester uses reconnaissance techniques to gather information about the target environment. They will then fingerprint applications, services and systems, gathering further information for exploitation and lateral movement. This process is repeated to gain the highest-level access to the targets to demonstrate the impact of an attempted compromise.

Who conducts a penetration test?

Our skilled CREST-approved penetration testers perform pentesting to simulate attacks using the same techniques used by hackers and cyber criminals.

How much does a penetration test cost?

The cost of a penetration test typically ranges between £5,000 and £30,000. The price depends on factors such as the scope, duration and complexity of the test. Testing large networks with thousands of systems is more expensive than testing small business networks. Similarly, testing large enterprise applications will cost substantially more than a small application with a single function.

Is penetration testing necessary?

Yes – penetration testing is a critical part of any security strategy. It helps identify and fix vulnerabilities before malicious actors can exploit them, validates your existing defences, and ensures compliance with industry standards.

What is CREST?

CREST is an international not-for-profit accreditation and certification body representing and supporting the technical information security market. Companies can become a CREST member and apply for CREST-accredited services. The application requires a rigorous assessment of companies’ processes, data security and service methodologies to ensure they adhere to a best practice standard.

Why should I use a CREST-approved pentesting company?

Working with a CREST-approved penetration testing provider ensures you’re in safe and experienced hands. You should have the confidence that your penetration test is thorough and comprehensive. Your provider must conduct a technically comprehensive test adhering to CREST’s information security and quality assurance requirements.

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In their words

Sentrium have extensive knowledge of security and penetesting, and have provided us with many valuable insights. We are grateful for their exemplary work and dedication to giving a top quality service.

Director, Manufacturing

Sentrium is a trusted partner we have used for several years. Their services are second-to-none, and the team’s communication, specialised knowledge, and flexibility are commendable.

IT Manager, Software Development

Working with Sentrium Security on our penetration testing was a pleasure. Their services were comprehensive, well organised, and delivered with professionalism. They get a 5/5 from us.

Chief Information Security Officer (CISO), Telecommunications

Sentrium surpassed our expectations. They identified vulnerabilities and provided recommendations that were very easy to follow. Their commitment to quality is apparent, and we gladly recommend them.

Chief Operating Officer, Financial Services

We engaged Sentrium for our annual pentesting. Their team demonstrated great skills, I was surprised to find they discovered some issues our previous company had missed! I will use them again next year.

Head of IT Security, International E-commerce

I’m impressed with the speed and quality of services provided by Sentrium. Great communication and a flexible, professional and approach throughout. I’ll certainly be using Sentrium again in the future!

Head of Technology Risk & Security, Financial Services

Sentrium has been really helpful in improving our cyber security. They keep in mind our budget and explain things clearly. Cyber security went from being an enigma to something we can tackle with confidence!

Project Manager, Charity Sector

Adam and James have been great to work with. Very clear communication from start to finish making the process very easy to complete whilst taking the time to understand our needs and queries.

Director, Software as a Service (SaaS) Company

Ready to discover your security gaps?

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