Infrastructure Penetration Testing
Expert-led, manual infrastructure penetration testing, from your perimeter to your domain controllers.
Your network infrastructure is the backbone of your organisation, and one of the most targeted attack surfaces in cybersecurity. Our CREST-accredited consultants test it the way a real attacker would: manually identifying, chaining, and exploiting vulnerabilities across your external perimeter and internal network, going well beyond what automated vulnerability scanning can surface.
Infrastructure Testing Overview
What Is An Infrastructure Penetration Test?
An infrastructure penetration test is a structured, expert-led security assessment of your IT network, covering the systems, services, and devices that make up your internal and external environment. Our consultants actively attempt to identify and exploit vulnerabilities, misconfigured services, and weak access controls to understand the real-world impact of a successful attack on your network.
Infrastructure testing is one of the most common drivers of compliance requirements. Whether you’re working towards ISO 27001 certification, undergoing an IT Health Check (ITHC), or simply building confidence in your network security posture, a thorough manual assessment is the most reliable way to understand your true exposure.
Infrastructure Test Coverage
What Our Infrastructure Testing Covers
Network Architecture & Segmentation
> Assessment of network design, VLAN configuration, & traffic segmentation
> Identification of unintended access paths between network zones
> Firewall rule review and egress filtering assessment
Network Devices
> Security configuration of routers, switches, firewalls, and load balancers
> Default credentials, weak authentication, and management interface exposure
> Firmware version analysis and known vulnerability identification
Active Directory & Domain Security
> Enumeration of domain users, groups, trusts, and Group Policy Objects
> Testing for Kerberoasting, Pass-the-Hash, and lateral movement paths
> Identification of privilege escalation routes to Domain Admin
Operating Systems & Patch Management
> Missing security patches and end-of-life software across live systems
> OS hardening assessment against industry baselines (CIS, NCSC)
> Identification of exploitable vulnerabilities in unpatched services
Service Configuration & Authentication
> Weak or default credentials across network services and management interfaces
> Insecure protocols in use - Telnet, FTP, SNMPv1/v2, NTLMv1, and others
> Authentication bypass and privilege escalation via misconfigured services
Data Exfiltration & Access Controls
> User role and privilege configuration across systems and services
> Data loss prevention controls and exfiltration route identification
> Access to sensitive shares, databases, and critical internal resources
Infrastructure Test Approach
How We Approach Infrastructure Testing
External Network Testing
Your external infrastructure is your public-facing attack surface, everything visible and reachable over the internet. Because it's publicly accessible, it can be discovered and targeted by attackers anywhere in the world, making it one of the highest-risk areas of your network.
Our external infrastructure testing identifies what you have exposed, uncovers vulnerabilities in internet-facing services, and actively attempts to establish a foothold on your network, the same first step a real attacker would take.
What our external testing covers:
> Discovery and enumeration of internet-facing assets and services
> Vulnerability identification and manual exploitation of exposed services
> Firewall and perimeter control assessment
> Attempted network ingress and foothold establishment
Internal Network testing
Your internal network is the environment an attacker reaches after bypassing your perimeter, or one an insider threat already operates within. Internal testing assesses what a malicious employee, compromised supplier, or attacker who has gained initial access could realistically achieve.
Our internal infrastructure testing maps your internal attack surface, identifies lateral movement paths, and assesses how far an attacker could escalate privilege, up to and including full domain compromise.
What our internal testing covers:
> Active Directory enumeration and attack path analysis
> Lateral movement and privilege escalation to Domain Admin
> Access control and user role configuration assessment
> Identification of sensitive data exposure and exfiltration routes
Our Test Process
Putting Your Infrastructure To The Test
Every infrastructure penetration test goes through a rigorous process to ensure you get the best possible results. Below we outline the key stages our testing goes through:.
Understand Your Requirements
No two networks are the same. We begin every engagement by understanding your environment, your compliance requirements, and what a successful test looks like for you, before putting forward a bespoke scoping proposal. Whether you need external-only, internal-only, or a combined assessment, we'll scope it precisely to your needs.
Manual, Expert-Led Testing
Your test is carried out by consultants with deep experience in network and infrastructure security. We use industry-standard tooling to support discovery and enumeration, but every finding is validated through manual exploitation, not automated output. This means real attack paths, confirmed impact, and findings your development and IT teams can act on with confidence.
Reporting Tailored To Your Organisation
Our reports are written for real audiences, not generated by a tool. Technical findings include full exploitation detail, confirmed impact, and clear remediation guidance for your IT and security teams. Executive summaries give leadership and compliance stakeholders what they need. Where required, we can map findings to specific compliance frameworks including ISO 27001 and PCI DSS.
Post-Test Remediation Support
We remain available after delivery to answer questions, support remediation prioritisation, and provide fix checks to confirm vulnerabilities have been resolved. Additional documentation for ISO 27001, ITHC, or PCI DSS audit purposes is available on request.
Frequently Asked Questions
Infrastructure Penetration Testing for Security-Mature Teams
If you’re already testing your internal and external infrastructure regularly, you’re likely weighing providers on depth and approach rather than the basics of what infrastructure testing covers. The questions below address how we handle internal and external testing, scoping around change and hybrid environments, and reporting, built around the concerns of teams testing on an ongoing cycle rather than a single annual assessment. If you don’t see your question answered here, get in touch and we’ll walk you through it directly.
Do you test internal and external infrastructure together, or as separate engagements?
They can be scoped either way. Internal and external infrastructure present different attack surfaces and often different risk priorities. External testing assesses what an internet-facing attacker can reach, while internal testing assumes a foothold already exists and focuses on lateral movement and privilege escalation. Many clients run both as part of the same engagement window for a fuller picture, but they can also be scoped and reported separately if that fits your testing cycle better.
Can infrastructure testing be run without disrupting production systems?
Yes, provided proper controls are in place, although zero risk is impossible to guarantee. We minimise production risk by agreeing on strict testing boundaries, exclusion lists, and constraints during the scoping phase. For end of life, or legacy systems, which may be more fragile under testing, we adjust techniques and intensity accordingly. If this is a concern, testing approaches will be agreed with you in advance.
How do you scope external infrastructure testing for a large or dynamic IP range?
Test scope will be confirmed before testing begins, and we can work from an asset list you provide or help identify your external footprint as part of scoping. For organisations with infrastructure that changes frequently (cloud-hosted services, dynamic IP allocation), we recommend re-confirming scope each testing cycle rather than relying on a static list from a previous engagement.
How do you factor in supply chain and third-party access risk during infrastructure testing?
Where third-party or supplier access forms part of your environment (VPN access, shared infrastructure, managed service provider connections), this can be included in scope, assessing whether that access is appropriately segmented and whether compromise of a third-party credential or connection could lead to broader network access.
How do you approach scoping for large and complex infrastructure environments?
Scoping complex environments begins with a collaborative discovery session to map your architecture, host counts, and critical path dependencies. Rather than applying a one-size-fits-all approach, we break down your environment by risk profile, functionality, and operational constraints.
We work with your team to:
Segment and Prioritise: Focus intensive testing on high-risk, internet-facing, or mission-critical assets while using targeted sampling for repetitive internal segments.
Define Test Boundaries: Identify active subnets, UK and multi-region cloud environments, third-party supply chain integrations, and legacy components to establish strict rules of engagement.
Align with Standards: Ensure the scoping framework satisfies your specific UK compliance and governance requirements, such as NCSC guidelines, ISO 27001, Cyber Essentials Plus, or FCA/PRA operational resilience expectations.
Establish Communication Paths: Set clear escalations and scheduling windows to ensure seamless coordination across multi-team or shift-based operational environments.
This approach ensures comprehensive coverage across your attack surface without risking business continuity.
How do you approach scoping if budget constraints prevent testing the entire infrastructure at once?
When budget limits full-scope coverage across a large estate, we tailor an approach that maximises risk reduction, rather than taking an arbitrary "cut-everything-in-half" approach. Depending on your security objectives, compliance deadlines, and available budget, we typically recommend one of four strategies:
Risk-Based Prioritisation (High-Value Asset Focus): We direct budget toward your most exposed assets, such as internet-facing systems, core Active Directory controllers, or systems handling sensitive UK/EU data subject to UK GDPR and PCI DSS, while deferring low-risk or isolated internal segments.
Representative Sampling: For repetitive, uniform infrastructure (such as regional branch offices, UK retail sites, or identical cloud worker nodes), we test a statistically valid sample set. This identifies systemic misconfigurations across the architecture without paying to test every identical host.
Phased Engagements: We break the broader scope into a multi-quarter or annual schedule aligned with your financial year. This spreads the investment across budget periods while systematically covering the full attack surface over time.
Hybrid Assessment (Vulnerability Assessment + Targeted Pen Test): We run automated scanning across the wider estate to flag low-hanging fruit, then deploy human testers to perform manual exploitation only on high-risk findings or critical operational paths.
This ensures you receive actionable, high-impact security insights without overspending or sacrificing testing quality on critical assets.
What does the infrastructure testing report include, and can we see a sample?
Each finding includes a risk rating, evidence of exploitation, and remediation guidance specific to your environment, including clear detail on attack paths where findings were chained together. We also map critical findings against affected hosts and network zones, so your infrastructure team can see exactly where exposure sits. Alongside the technical detail, an executive summary gives stakeholders the headline risk picture without needing to work through every finding.
A sample report is available to download directly here.
Can you assess our exposure to common initial access techniques like phishing-driven credential theft or MFA fatigue attacks?
This is typically scoped as part of a broader engagement (such as a red team or purple team) rather than standard infrastructure testing alone, since it involves the human and identity layer as well as the network. If this is a specific concern, flag it at scoping and we can build it into the engagement or recommend the right service for it.
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Find Out More About Our Infrastructure Penetration Testing
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Infrastructure Insights
The Latest Insights From The Pentest Team
The threat landscape doesn’t stand still, and neither do we. Our consultants invest in ongoing security research, CTF competitions, and responsible vulnerability disclosure to stay at the cutting edge of offensive security. The techniques we develop in the lab are the techniques we bring to your engagement.
