Senior Offensive Security & Penetration Tester

EY; Irvine (CA); On-site; USD 140,000 - 210,000; Full time

Job summary

EY is seeking a Senior Attack & Penetration Tester to lead complex offensive security engagements across client environments with threat-informed methods and MITRE ATT&CK.

You will plan, execute, and coordinate penetration tests on external/internal networks, AD, cloud, wireless, web, mobile, and APIs. You will translate findings into remediation strategies, mentor junior staff, and work with clients to improve security controls.

Qualifications

• Bachelor's degree in CS, CE, Cybersecurity or related field and at least five years of offensive security experience.
• Hands-on experience planning and executing advanced red team engagements, including adversary emulation and objective-based operations.
• Advanced experience in external and internal network penetration testing across AD, cloud, wireless, web, mobile, and APIs.
• Experience assessing Active Directory environments, identity-based attack paths, and security configurations.
• Cloud security testing experience, including IAM and exposed services.
• Wireless security assessments and enterprise configurations experience.
• Experience testing web/mobile apps and APIs using manual techniques and standard methodologies.
• Ability to develop practical remediations and validate findings with client teams.
• Experience scripting or programming to automate testing and tooling.

Responsibilities

• Plan, lead, and execute complex penetration tests and red team engagements across diverse environments.
• Apply intelligence-led, threat-informed testing aligned with MITRE ATT&CK.
• Translate testing results into actionable risk insights for technical and executive audiences.
• Collaborate with client teams to validate weaknesses and develop remediation strategies, including AD hardening.
• Lead technical workstreams, mentor junior staff, and contribute to methodology development.
• Stay current on vulnerabilities, attacker tactics, and offensive security tooling.

Skills

Penetration testing

Red team

Threat-informed testing

Active Directory security

Cloud security testing

Wireless security

Web testing

Mobile testing

API testing

Scripting languages

Mentoring juniors

Executive communication

MITRE ATT&CK

Education

Bachelor's degree in CS/CE/Cybersecurity

Job description

EY is seeking a Senior Attack & Penetration Tester to lead complex offensive security engagements across client environments with threat-informed methods and MITRE ATT&CK.

You will plan, execute, and coordinate penetration tests on external/internal networks, AD, cloud, wireless, web, mobile, and APIs. You will translate findings into remediation strategies, mentor junior staff, and work with clients to improve security controls.