Penetration Tester

“I am hugely excited about my future and the future of CyberOne. I have enjoyed my time here immensely and have learnt a huge amount in a short space of time, year-for-year I've learnt more here than I have at Microsoft and PwC.” - CyberOne Consultant

About CyberOne

CyberOne is a pure-play Microsoft security partner dedicated to helping enterprises realise the full value of the Microsoft Security portfolio-across Defender XDR, Sentinel, Entra, Purview, Intune, Copilot for Security and more. We combine deep technical expertise with outcome-driven services that accelerate secure cloud adoption, modernise threat protection and simplify compliance.

Job Title: Penetration Tester

Location: Remote

Employment Type: Full-time

We are seeking a highly skilled and motivated Penetration Tester to join our Cyber Security team. The successful candidate will be responsible for conducting advanced penetration testing engagements across enterprise environments, with a particular focus on Active Directory (AD) security assessments. This role requires hands-on experience identifying, exploiting, and documenting security vulnerabilities while providing practical remediation recommendations to strengthen clients' security posture.

Key Responsibilities

• Conduct comprehensive penetration testing engagements against enterprise infrastructure, networks, systems, and applications.

• Perform manual and automated security assessments to identify vulnerabilities, weaknesses, and potential attack vectors.

• Assess and exploit Active Directory environments, identifying security risks including:

  • Misconfigurations

  • Privilege escalation paths

  • Lateral movement opportunities

  • Credential theft vulnerabilities

  • Excessive permissions and insecure delegation

• Execute network and system exploitation activities to validate security weaknesses and assess their impact.

• Evaluate the effectiveness of security controls, hardening measures, and defensive configurations within Active Directory environments.

• Simulate real-world attack scenarios to assess organizational resilience against cyber threats.

• Develop detailed technical reports outlining attack paths, findings, business impact, proof-of-concept evidence, and remediation recommendations.

• Present technical findings to both technical and non-technical stakeholders.

• Work closely with internal teams and clients to support remediation efforts and provide security best-practice guidance.

• Stay up to date with emerging threats, attack techniques, exploitation methodologies, and security technologies.

Required Skills & Experience

• Proven experience conducting penetration tests across enterprise networks and infrastructure.

• Strong knowledge of Windows environments and Active Directory security.

• Experience identifying and exploiting Active Directory vulnerabilities and attack paths.

• Excellent understanding of:

  • Network protocols and architecture

  • Windows Server administration

  • Authentication mechanisms (Kerberos, NTLM)

  • Privilege escalation techniques

  • Lateral movement methodologies

• Hands-on experience with penetration testing and red team tools such as:

  • BloodHound

  • Mimikatz

  • CrackMapExec

  • Impacket

  • Nmap

  • Burp Suite

  • Metasploit

  • Responder

• Familiarity with vulnerability assessment and security testing methodologies including OWASP, NIST, and PTES.

• Strong technical documentation and report-writing skills.

• Excellent analytical, troubleshooting, and problem-solving abilities.

Preferred Qualifications

• Offensive Security Certified Professional (OSCP)

• CRTO (Certified Red Team Operator)

• CREST Registered Penetration Tester (CRT) or CREST Certified Infrastructure Tester (CCT INF)

• GIAC Penetration Tester (GPEN)

• Relevant Microsoft security certifications

• Experience delivering internal or external client-facing security assessments