Internal infrastructure penetration testing
Why choose Citation Cyber?
Expert support
Testing by CHECK-approved and CREST-certified penetration testers.
Single platform
Delivered through Atlas, your one stop shop for managing cyber risk.
Every sector
SMEs, public sector, care providers, early years, education, professional services.
What is internal network penetration testing?
Internal network penetration testing, also known as internal infrastructure penetration testing or internal pen testing, simulates the actions of an attacker who has already gained access to your network. That could be through a compromised device, stolen credentials, or malicious insider activity.
Testing focuses on what happens next: how easily an attacker could move around your network, escalate privileges, access sensitive systems, or gain full control of your domain.
Why internal infrastructure penetration testing matters
Many serious breaches happen after an attacker gets inside the network, often through phishing, compromised credentials, or third-party access.
Internal penetration testing helps you:
- Understand how exposed your internal network is
- Find weaknesses that allow lateral movement and privilege escalation
- Reduce domain compromise and further disruption risk
- Strengthen defences against insider threats and breached accounts
- Validate existing security controls and monitoring
What’s included in our internal
penetration testing services
Network mapping and asset discovery
Internal services, systems, and trust relationships identification
Exploit identified vulnerabilities where safe and appropriate
Testing for privilege escalation and lateral movement
Authentication, access controls, and segmentation assessment
Evaluate how an attacker could reach critical systems
Prioritised risks plus practical remediation guidance
Free retests on high and critical vulnerabilities
Our internal penetration testing process
Assess and secure your internal network in five clear steps with our CHECK and CREST certified ethical hackers.
Discovery phase
We learn about your environment, users, goals.
Pre-testing
Confirm scope, approach, and logistics, including setup.
Testing
UK-based experts exploit vulnerabilities to show current risks.
Reporting
You’ll receive a clear breakdown of findings, fixes and actions in Atlas.
Review, retest
Walk through the results and retest high/criticals at no extra cost.
How we test your internal environment
Before any testing takes place, you’ll have a kick off call with an ethical hacker to walk you through what we’ll do, discuss potential risks, and answer any questions you have.
White box
We test with full knowledge of your external systems to understand how far an attacker could go if your perimeter was breached.
Best for: Deep assurance, compliance, and mature IT environments.
Grey box
We test with limited information to simulate the access a trusted third party or compromised user might have.
Best for: Practical risk insight without full system exposure.
Black box
We test with no prior knowledge, just like a real attacker scanning the internet for weaknesses.
Best for: First-time testing or establishing a baseline.
What happens next?
After the assessment, you’ll get a clear, actionable report that shows what’s vulnerable, how serious it is, and what to fix first in our all-in-one platform Atlas.
In your report, you’ll see:
High-level executive summary
Technical and remediation summaries
Vulnerabilities with clear risk ratings (Citation Score & CvSS Score)
Description, impact, evidence of each vulnerability
Short- and long-term remediation guidance
Technical detail for your IT/MSP
Free retest results
What is CHECK-certified penetration testing?
CHECK is a penetration testing framework created and managed by the National Cyber Security Centre (NCSC). It’s intended for UK government departments and public sector bodies, providing reassurance that security has been properly tested before a contract is signed.
It’s the UK government’s gold standard for how testing should be done.
Find out more about CHECK pen testing here.
Protect your systems all year round
Penetration testing gives you a deep understanding of how your cyber security holds up right now, but threats can happen at any time. We also offer vulnerability scanning that provides you year-round, 24/7 protection, so you can catch weaknesses as and when they occur.
UK breaches 2026
average significant attack cost per business
total business breaches
Why our customers love us
Expert protection against cyber threats
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Amanda Bailey
Quorum Logistics Support Limited
An extremely friendly, knowledgeable, and experienced team from start to finish.
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Brian Wheatley
Medical-Legal Appointments Ltd
Citation Cyber have been outstanding throughout what has been a challenging test this year, Lee (Cyber Essentials Assessor) has been brilliant from start to finish, he’s understood the challenges and advised and accommodated every question. BIG thanks from MLA.
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Clare Baldwin
Quantum Health Solutions
We were really appreciative of Citation Cyber’s Responsiveness to us as our penetration testing needed to be completed very quickly and were able to accommodate this. Communication from the team was really good and the report was comprehensive and easy to follow for us and our developers.
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Jason Cass
Royal British Legion Industries
A fantastic service done by Citation again for our Cyber Essentials Plus award. The engineers within the company work to a very high standard and work well with the customer to explain along the way anything that is raised. They are on-hand to answer any questions, and explain the findings and resolution to aid the certification. A top-quality company that is highly recommended!
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Liam Booth
Cubic Interactive Ltd
Out of all the companies we approached, Citation were the first to respond to our requests for meetings, they were always available to ask questions to, and were the only ones who really took time to understand us, how our products have been developed and our specific testing needs. I would have no reservations about recommending Citation Cyber to others. Everyone we have spoken to at Citation Cyber have been genuinely nice people, nothing felt ‘salesy’ and we never felt we were being pushed to have anything we didn’t need.
What you can test
What you can test
Our penetration testing services let you test anything that connects to the internet. These tests uncover vulnerabilities and allow us to deliver tailored recommendations that safeguard sensitive data and the systems supporting it.
Penetration Testing
Identify risks with expert-led simulated attacks to protect your data and systems.
Cyber Essentials Certification
Achieve Cyber Essentials certification to defend against common threats, whatever your business size.
Employee Awareness Training
Empower your team to be your first line of defence with easy, interactive training.
Phishing Simulator & Bespoke Campaigns
Simulations to teach your staff how to spot and stop phishing scams easily.
Intelligent Monitoring & Vulnerability Scanning
Stay protected between pen tests with continuous scanning and real-time breach alerts.
Cyber Security Consultancy
Tailored advice for compliance, ransomware plans, and board-level cyber support.
Cyber Security Compliance
Simplify policies with NCSC-approved templates and hassle-free management tools.
Frequently asked questions
Citation Cyber work with you to make sure any penetration test causes minimal disruption to your operations. If you want, we’ll test in staging or development environments and share issues in real time so you can act quickly.
Internal infrastructure pen testing is conducted within an organisation’s systems to understand what could happen if a hacker gained access to its network.
In contrast, external infrastructure penetration testing is carried out remotely by an ethical hacker. They’ll simulate real-world attacks on systems such as servers, firewalls, IP addresses, and VPN gateways to identify vulnerabilities and exploit them.
Discover our external infrastructure penetration testing service here.
Internal infrastructure penetration tests take different amounts of time depending on your infrastructure and systems. Get in touch with our team to understand how long yours might take.
Your penetration testing following up report has all the information your need to understand what vulnerabilities you have and how to fix them. If you need help understanding the report and what it means, we can walk you through the findings and give you any information you need.
Yes, we work closely with MSPs and IT suppliers to support their work and understand your systems. We can also share remediation information and advice following an engagement.
How much an internal infrastructure penetration test costs depends on how long the testers need to complete the engagement. That depends on your infrastructure, systems and the testing type you choose. Get in touch with our team to find out about pricing.
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