Senior Offensive Security Engineer

FocusKPI is seeking a Senior Offensive Security Engineer (Web & AI systems) to join one of our clients, a high-tech SaaS company. 

Team is looking for a Senior Offensive Security Engineer to proactively identify, exploit, and help eliminate security weaknesses across their web platforms and AI/ML systems. In this role, you will think like an attacker, operate with engineering rigor, and work closely with product, platform, and AI teams to raise the security bar across the organization. You will lead complex penetration tests, design novel attack techniques for web and modern AI-powered applications, and influence secure-by-design architecture at scale.

Work Location: Mountain View, CA (Onsite role, 5 days/week onsite)
Duration: 12-month contract with potential to convert depending on the candidate's performance
Pay Range: $60+/hr

**No C2C resumes are considered**
 

Position Responsibilities:

• Conduct offensive security assessments on large-scale web applications, REST APIs, and cloud-backed services.
• Identify and validate vulnerabilities, including injection flaws, access control issues, authentication/authorization weaknesses, SSRF, deserialization, and logic bugs.
• Evaluate LLM-based systems and AI agents for prompt injection, data exfiltration, model abuse, and jailbreaks
• Design and execute red–team–style engagements that simulate real-world adversaries.
• Develop custom exploitation tools, PoCs, and fuzzers for web and AI attack surfaces.
• Identify systemic security weaknesses and collaborate with engineering teams to drive long-term mitigations.
• Review architectures and designs for new products from an attacker's perspective.
• Produce clear, actionable security reports and present findings to technical and executive stakeholders.

Required Qualifications:

• Master’s degree in Computer Science, Computer Engineering, Information Security, or a closely related technical field.
• A doctorate (PhD) in a relevant field is a plus, but not required.
• 5+ years of experience in offensive security, penetration testing, or red teaming.
• Experience with browser security, red teaming, and penetration testing is a non-negotiable skill for this role.
• Deep expertise in web application security.
• Strong understanding of API security.
• Vulnerability findings: Identifying and prioritizing vulnerabilities across a network of 1,000+ devices to support risk management efforts. Conducting regular vulnerability assessments to detect and address security weaknesses in various systems and applications.
• Proficiency in at least one scripting or programming language (Python, Go, JavaScript, or similar).
• Strong knowledge of common exploitation techniques and attacker tooling.

• Prior work on adversarial ML, red-teaming AI systems, or secure LLM pipeline design.
• Experience with cloud security (AWS, GCP, Azure) and containerized environments.
• Hands-on experience testing AI/ML or LLM-based systems, or strong motivation with demonstrated research in this area.
• Background in security research, published CVEs, CTF experience, blog posts, or conference talks.
• OSCP, OSEP, OSWE, CRTO, or similar.

• An attacker-first mindset with strong engineering discipline.
• Ability to go beyond scanners and find novel, high-impact vulnerabilities.
• Clear communicator who can translate complex exploits into actionable fixes.
• Curiosity about emerging threats, especially in AI security.
• Ownership mentality and comfort operating in ambiguous problem spaces.

Thank you!

FocusKPI Hiring Team

Founded in 2010, FocusKPI, Inc. (FocusKPI) is a data science and technology firm specializing in predictive analytics practice and methodologies. FocusKPI is a US company headquartered in Silicon Valley, California, with an East Coast office in Boston, Massachusetts.

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