Application Security Penetration Engineer

Citi, the leading global bank, has approximately 200 million customer accounts and does business in more than 160 countries and jurisdictions. Citi provides consumers, corporations, governments, and institutions with a broad range of financial products and services, including consumer banking and credit, corporate and investment banking, securities brokerage, transaction services, and wealth management.

As a bank with a brain and a soul, Citi creates economic value that is systemically responsible and in our clients’ best interests. As a financial institution that touches every region of the world and every sector that shapes your daily life, our Operations & Technology teams are charged with a mission that rivals any large tech company. Our technology solutions are the foundations of everything we do from keeping the bank safe, managing global resources, and providing the technical tools our workers need to be successful to designing our digital architecture and ensuring our platforms provide a first-class customer experience.

We reimagine client and partner experiences to deliver excellence through secure, reliable, and efficient services.

Our commitment to diversity includes a workforce that represents the clients we serve from all walks of life, backgrounds, and origins. We foster an environment where the best people want to work. We value and demand respect for others, promote individuals based on merit, and ensure opportunities for personal development are widely available to all. Ideal candidates are innovators with well‑rounded backgrounds who bring their authentic selves to work and complement our culture of delivering results with pride.

If you are a problem solver who seeks passion in your work, come join us. We’ll enable growth and progress together.

Citi is seeking an Application Security Penetration Tester to join its Offensive Security team, conducting deep‑dive vulnerability assessments across web applications, mobile, thick clients, APIs, microservices, and emerging Generative AI/LLM implementations. This role is well‑suited for either an experienced penetration tester looking to deepen their offensive security career or a software developer/engineer seeking to transition into cybersecurity.

The analyst will manually identify, research, validate, and safely exploit known and zero‑day vulnerabilities, then translate technical findings into clear risk guidance for developers, architects, and ML engineers. A key focus of the role is researching and applying LLM‑based security testing techniques to uncover complex, non‑obvious vulnerabilities that evade traditional automated and manual testing. The team supports pentesting of the firm’s most critical applications while actively researching AI/LLM‑driven automation to enhance pentest effectiveness.

• Conduct manual vulnerability assessments and penetration testing across applications and/or infrastructure.
• Identify and validate potential security vulnerabilities across Citi applications, APIs, cloud‑native services, and AI/ML architectures.
• Engineer functional proof‑of‑concept code and exploit scenarios to demonstrate the exploitability and tangible impact of identified security weaknesses.
• Research and use LLM‑based security testing harnesses to uncover deeply embedded, non‑obvious vulnerabilities.
• Identify multi‑step business logic abuse chains, cryptographic flaws, and complex privilege escalation paths that evade manual and traditional automated testing.
• Accurately document discovered vulnerabilities, reproduction steps, attack chains, and risk ratings in standardized assessment reports.
• Report and articulate vulnerability assessment results to both technical and non‑technical audiences.
• Clearl…