Security Engineer, Application Security

Quartermaster AI is hiring a Security Engineer, Application Security to own and strengthen the security of its cloud services, APIs, data pipelines, and applications across distributed edge systems. The role leads threat modeling, secure design and code reviews, vulnerability remediation, security tooling and automation, and development of the secure software development lifecycle.

Responsibilities:

• Lead threat modeling and secure design reviews for new and existing services, identifying and mitigating risk early in the development lifecycle
• Perform in-depth secure code reviews and full-scope application security assessments — whitebox, greybox, and blackbox — across web, API, cloud, and backend services
• Build, integrate, and tune application security tooling in CI/CD — SAST, DAST, SCA, secret scanning, and static analysis platforms such as CodeQL — to catch vulnerabilities before they ship
• Triage, prioritize, and drive remediation of application vulnerabilities together with engineering teams, ranking work by real-world risk and business impact
• Develop automation and paved-road tooling that eliminate entire classes of weaknesses and make the secure path the default path for developers
• Serve as the application security subject-matter expert for engineers and architects, steering product design toward secure-by-default patterns
• Define and mature the secure software development lifecycle (SDLC), secure coding standards, and security requirements across the engineering organization
• Own or support the vulnerability disclosure and bug bounty process — scoping, validating submissions, performing root-cause analysis, and coordinating fixes with engineering
• Strengthen software supply chain security, including dependency management, artifact and commit signing, and build/pipeline integrity
• Partner with the security operations team on application-layer incidents, providing code-level expertise during investigation and remediation
• Deliver developer-focused security training and champion a security-aware engineering culture through enablement rather than gatekeeping

Requirements:

• 5–8 years in application security, product security, or software engineering with a strong security focus
• Software development experience in one or more modern languages (e.g., Python, Go, Java, JavaScript/TypeScript, Rust, or C/C++) and the ability to read and reason about production code
• Demonstrated experience evaluating code for vulnerabilities and weaknesses, and leading threat modeling and security design reviews
• Hands-on experience with application security tooling — SAST, DAST, SCA, and static analysis platforms such as CodeQL — and integrating them into CI/CD pipelines
• Strong understanding of the OWASP Top 10 (web and API), CWE, common vulnerability classes, and secure coding practices
• Experience securing modern architectures — microservices/SOA, REST/gRPC APIs, containers, and cloud environments (AWS, Azure, or GCP)
• Experience performing black-box and grey-box testing of web applications and APIs
• Proven track record driving vulnerability remediation by partnering with engineering teams rather than blocking them
• Excellent written and verbal communication skills, with the ability to influence engineers and explain risk to both technical and non-technical audiences
• Must be a U.S. citizen
• Bachelor's degree in Computer Science, Cybersecurity, or equivalent hands-on experience
• Active U.S. security clearance, or eligibility and willingness to obtain and maintain one
• Industry certifications such as OSCP, OSWE, GWAPT, GWEB, CSSLP, or Burp Suite Certified Practitioner
• Experience building “paved road” / secure-by-default frameworks and developer self-service security tooling
• Experience with software supply chain security (SLSA, in-toto, Sigstore) and artifact/commit signing
• Experience with infrastructure-as-code and cloud-native security (Terraform, Kubernetes)
• Contributions to bug bounty programs, published CVEs, security research, or open-source security tooling
• Familiarity with securing embedded, edge, or robotics/IoT software
• Familiarity with defense-sector compliance frameworks (NIST 800-171, CMMC) as they relate to secure development
• Prior experience in a startup, defense, intelligence, or critical-infrastructure environment