Penetration Tester

OpenKrill; United States; On-site; USD 90,000 - 130,000; Full time

Job summary

CyberOne is a pure-play Microsoft security partner dedicated to helping enterprises realise the full value of the Microsoft Security portfolio. We are seeking a Penetration Tester to conduct comprehensive assessments of enterprise networks, systems, and Active Directory environments from a remote, full-time location.

You will perform both manual and automated testing, document findings with remediation guidance, and present results to stakeholders.

Qualifications

• 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.
• Familiarity with vulnerability assessment methodologies including OWASP, NIST, and PTES.
• Excellent technical documentation and report-writing skills.
• Strong analytical, troubleshooting, and problem-solving abilities.

Responsibilities

• Conduct penetration testing engagements against enterprise networks, systems, and applications.
• Perform manual and automated security assessments to identify vulnerabilities.
• Assess and exploit Active Directory environments, including misconfigurations and privilege escalation.
• Execute network and system exploitation activities to validate weaknesses.
• Develop detailed technical reports with attack paths, findings, business impact, 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.

Skills

Penetration testing

Active Directory security

Windows environments

Privilege escalation

Lateral movement

Network protocols

Security reporting

Analytical thinking

Troubleshooting

Tools

BloodHound

Mimikatz

CrackMapExec

Impacket

Nmap

Burp Suite

Metasploit

Responder

Job description

“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

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