Security Engineer

Valiant Technologies LLC; Sunnyvale (CA); On-site; USD 160,000 - 260,000; Full time

Job summary

Valiant Technologies LLC is recruiting a security engineer specializing in ERD security, threat modeling, and AI agent security. You will assess architecture, data flows, and third-party sharing across applications and cloud environments, with hands-on testing and tooling to improve risk mitigation.

The role emphasizes practical mitigations, collaboration with engineering and privacy teams, and the ability to implement automated security workflows and adversarial testing.

Qualifications

• 5+ years of relevant professional experience, including 3+ years in security engineering or a related security role.
• Experience conducting security design reviews, threat modeling, and privacy risk assessments.
• Hands-on penetration testing experience and a strong understanding of application, API, cloud, and data security.
• Software development or scripting experience, with the ability to build tools and automate security workflows.
• Familiarity with AI agent architectures and risks involving prompt injection, tool execution, permissions, and data access.

Responsibilities

• Conduct ERD security and privacy reviews across applications, APIs, cloud infrastructure, and AI systems, identifying risks in authentication, data handling, retention, and third-party sharing.
• Perform threat modeling, identify abuse cases, recommend mitigations, and work with engineering teams to address risks before deployment.
• Assess and test AI agents, including third-party and internally developed agents, through adversarial testing for data exposure, permissions, and external integrations.
• Build security automation tools and AI-assisted workflows to streamline reviews, evidence collection, and testing coverage.
• Conduct targeted penetration testing to validate security assumptions and identify exploitable vulnerabilities in services, APIs, and AI agents.
• Drive remediation and share knowledge by communicating findings, validating fixes, and developing guidance to prevent recurring issues.

Job description

What you’ll do:

• Conduct ERD security and privacy reviews: Evaluate engineering proposals, architecture, and data flows across applications, APIs, cloud infrastructure, and AI systems. Identify risks involving authentication, authorization, sensitive data handling, data minimization, retention, and third-party sharing.
• Perform threat modeling: Identify potential abuse cases and attack paths, recommend mitigations, and work with engineering teams to address risks before deployment.
• Assess and test AI agents: Evaluate third-party and internally developed coding and work-focused agents through adversarial testing. Examine prompt injection, tool use, permissions, data access, sensitive data exposure, and external integrations.
• Build security automation: Develop tools and AI-assisted workflows to streamline ERD reviews, threat modeling, evidence collection, and security testing, increasing assessment coverage and consistency.
• Conduct targeted penetration testing: Validate security assumptions and identify exploitable vulnerabilities in critical services, applications, APIs, and AI agents.
• Drive remediation and share knowledge: Communicate actionable findings, validate fixes, and develop guidance that helps teams prevent recurring security and privacy issues.

Required qualifications:

• 5+ years of relevant professional experience, including 3+ years in security engineering or a related security role.
• Experience conducting security design reviews, threat modeling, and privacy risk assessments.
• Hands-on penetration testing experience and a strong understanding of application, API, cloud, and data security.
• Software development or scripting experience, with the ability to build tools and automate security workflows.
• Familiarity with AI agent architectures and risks involving prompt injection, tool execution, permissions, and data access.
• Strong written and verbal communication skills, including the ability to explain risks and recommend practical mitigations.
• Ability to work independently with minimal supervision and collaborate across engineering, security, and privacy teams.
• Bachelors or master’s degree in computer science, cybersecurity, or a related field, or equivalent practical experience.

Preferred qualifications:

• Experience assessing AI agents, LLM applications, or third-party AI platforms.
• Experience building AI-powered security review or testing automation.
• Experience evaluating vendor security readiness and handling sensitive or business-critical data.
• Relevant security certifications, such as OSCP or CISSP.
• A passion for learning, teaching, and improving security practices.

We are an equal opportunity employer. All aspects of employment including the decision to hire, promote, discipline, or discharge, will be based on merit, competence, performance, and business needs. We do not discriminate on the basis of race, color, religion, marital status, age, national origin, ancestry, physical or mental disability, medical condition, pregnancy, genetic information, gender, sexual orientation, gender identity or expression, national origin, citizenship/ immigration status, veteran status, or any other status protected under federal, state, or local law.