Offensive Security Researcher, Senior

Momentum; San Francisco (CA); On-site; USD 150,000 - 210,000; Full time

Job summary

Leadout Capital is seeking a Senior Offensive Security Researcher with an attacker mindset to identify, analyze, and remediate vulnerabilities across our products and platforms. You will influence design decisions, drive secure-by-default initiatives, and advance application security maturity.

You will lead manual testing, architectural analysis, and threat modeling to uncover root causes and systemic issues, partnering with engineers to implement scalable remediations and secure designs.

Qualifications

• 7+ years of experience in Application Security or Offensive Security.
• Experience independently finding and remediating vulnerabilities in complex applications.
• Deep understanding of Web application security (OWASP Top 10 and beyond), authentication/authorization flaws, API security, injection attacks, logic flaws, and access control bypasses.
• Hands-on experience with manual security testing beyond automated tools.
• Ability to translate complex security findings into clear, actionable guidance for engineers and leadership.
• Strong communication and collaboration skills with a track record of influencing engineering teams.

Responsibilities

• Lead offensive security assessments (manual testing, code review, architectural analysis, threat modeling) across application ecosystems.
• Identify critical, high-impact, and systemic vulnerabilities alongside isolated issues.
• Drive security research to identify emerging attack vectors, abuse cases, and bypass techniques relevant to our apps and platforms.
• Partner with software engineers, tech leads, and architects to explain risk, impact, and exploitability; design and implement effective remediations.
• Ensure fixes are scalable, maintainable, and aligned with engineering realities.
• Lead Secure by Default initiatives by applying guardrails, patterns, and baseline controls; remediate insecure defaults and unsafe configurations.
• Influence application and platform designs early to prevent vulnerabilities before release.
• Set and apply security standards, best practices, and architectural guidance during development.
• Mentor engineers by sharing security knowledge and offensive techniques.
• Collaborate with detection, monitoring, and incident response teams to improve visibility into real-world exploitation.

Skills

Offensive security

Application security

Threat modeling

Code review

Mentoring engineers

Communication

Job description

The Experience

We are looking for a Senior Offensive Security Researcher with an attacker mindset to discover, analyze, and remediate security vulnerabilities across our products and platforms.

This role focuses on identifying root causes, architectural weaknesses, and recurring security anti-patterns, and driving secure-by-default solutions that prevent vulnerabilities.

You will work alongside and influence engineering teams to shape design decisions, improve security posture, and advance overall application security maturity.

What You'll Actually Be Doing

• Lead offensive security assessments (manual testing, code review, architectural analysis, threat modeling) across application ecosystems.
• Identify critical, high-impact, and systemic vulnerabilities alongside isolated issues.
• Drive security research to identify emerging attack vectors, abuse cases, and bypass techniques relevant to our applications and platforms.
• Partner closely with software engineers, tech leads, and architects to: Explain risk, impact, and exploitability. Design and implement effective remediations. Ensure fixes are scalable, maintainable, and aligned with engineering realities.
• Lead Secure by Default initiatives by: Applying security guardrails, patterns, and baseline controls. Remediating insecure defaults and unsafe configurations. Preventing vulnerabilities through platform-level and framework-level updates.
• Influence application and platform designs early in the development lifecycle to prevent vulnerabilities before release.
• Set and apply security standards, best practices, and architectural guidance during application development.
• Mentor engineers and peers by sharing security knowledge and offensive techniques.
• Collaborate with detection, monitoring, and incident response teams to improve visibility into real-world exploitation.

You're Our Person If...

• 7+ years of experience in Application Security or Offensive Security with an attacker mindset.
• Demonstrated experience independently finding and remediating vulnerabilities in complex applications.
• Deep understanding of: Web application security (OWASP Top 10 and beyond) Authentication & authorization flaws API security Injection attacks, logic flaws, and access control bypasses Secure design and threat modeling
• Hands-on experience with manual security testing (beyond automated tools).
• Ability to translate complex security findings into clear, actionable guidance for engineers and technical leadership.
• Strong communication and collaboration skills, with a track record of influencing engineering teams.

Even Better If...

• Published security research or CVEs (technical blogs, advisories, whitepapers, or conference presentations).
• Experience implementing platform-level or framework-level security improvements.
• Background in vulnerability discovery, security research, or red teaming.
• Experience implementing Secure by Default or security-by-design concepts.
• Familiarity with cloud-native architectures, microservices, and distributed systems.
• Ability to balance security requirements with product velocity and developer experience.