Offensive Security. Defensive Confidence.
Custodian Consulting is a UK-based offensive security firm built by penetration testers, for organisations that refuse to gamble on their security posture.
Our team holds CREST, CHECK, OSCP, and OSCE certifications. We have delivered engagements across NHS trusts, central government departments, financial services, and critical national infrastructure. Every finding we report is exploitable, every recommendation is actionable.
We do not sell fear. We sell evidence. Our reports give your board the clarity to make informed decisions about risk, and your engineers the technical detail to fix what matters.
End-to-end offensive security services, from scoping through to remediation validation. Every engagement is bespoke, every report is board-ready.
Internal and external network penetration testing. We enumerate, exploit, and pivot through your infrastructure exactly as a real attacker would — then tell you how to stop us.
Learn more →OWASP-aligned assessment of your web applications, APIs, and authentication flows. We find the injection points, logic flaws, and misconfigurations that automated scanners miss.
Learn more →iOS and Android application testing, wireless network auditing, and rogue access point detection. We assess your mobile attack surface from device to backend.
Learn more →Phishing campaigns, vishing, physical security assessments, and pretexting. We test the human layer of your defences with realistic, controlled adversary simulations.
Learn more →When a breach occurs, speed matters. Our IR team provides rapid triage, forensic analysis, containment strategy, and evidence-grade reporting for legal and regulatory compliance.
Learn more →End-to-end ransomware incident management. From initial containment and decryption assessment through to infrastructure rebuild and hardened redeployment.
Learn more →We are not a reseller with a scanner. We are hands-on-keyboard operators who understand your threat landscape.
Certified to test UK government and CNI systems. Our testers hold individual CREST qualifications at CRT and CCT level.
Executive summaries your leadership team can act on, technical appendices your engineers can build from. No filler, no recycled scanner output.
Automated tools find the low-hanging fruit. Our testers chain vulnerabilities, abuse business logic, and identify the attack paths that matter.
Trusted by NHS trusts, local authorities, MOD suppliers, and FTSE-listed organisations. We operate under NDA with the discretion your sector demands.
Most engagements scoped within 48 hours and scheduled within two weeks. Emergency incident response available with same-day mobilisation.
We do not just find problems and walk away. Every engagement includes a free retest window so you can verify your fixes hold under pressure.
Tell us what you need secured. We will scope the engagement, provide a fixed-price quote, and schedule your test — typically within two weeks.