Principal Security Researcher

Location: Arlington, VA, US

Employment Type: FULL_TIME

Overview

We’re building a new security research team focused on rapid triage, reverse engineering, vulnerability research, and proof-of-concept exploit development. We’re looking for a hands-on technical lead who can conduct difficult investigations while establishing the team’s research practices, tooling, and quality standards.

 

Practical experience with LLMs and associated agent harnesses is required. You’ll help integrate these tools throughout the research process and establish how their outputs are tested and verified.

 

Pay Range $142,000 - $222,000

 

The pay range for this position is a general guideline only and not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, geographic location, and any applicable laws.

Responsibilities

In this role, you will:

• Lead investigations from initial triage through root-cause analysis, exploitability assessment, PoC development, and reporting.
• Reverse engineer unfamiliar software and systems to identify vulnerabilities and understand their impact.
• Prioritize research, manage technical uncertainty, and help the team balance rapid assessments with deeper investigations.
• Review findings, exploits, and reports for technical accuracy, reproducibility, and clarity.
• Develop and improve LLM-assisted research workflows, including tool integration and evaluation.
• Mentor researchers and establish reusable tooling, documentation, and research standards.

Qualifications

You should bring:

 

• At least 7 years in security research, reverse engineering, exploit development, or closely related work, including substantial direct vulnerability research.
• Bachelor’s degree in Computer Engineering, Computer Science, or a related technical field. Additional years of experience may substitute for degree. 
• A record of independently completing complex investigations and producing reliable PoCs.
• Experience leading technical projects, reviewing research, or mentoring other researchers.
• Hands-on familiarity with LLMs and agent harnesses, including their limitations and methods for validating results.
• Strong programming, debugging, and technical writing skills.
• The judgment to communicate what is confirmed, what remains uncertain, and what deserves further investigation.

Preferred:

• Experience building research teams, extending agent harnesses, or developing fuzzing and analysis infrastructure would be valuable.

Security Clearance:

• Active Top Secret/SCI clearance.
• U.S. Citizenship is required.

About i3

i3 is a technically diverse, 100% team member owned business, headquartered in Huntsville, Alabama specializing in missile and aviation systems engineering and logistic services, electronic warfare and electromagnetic effects analysis, UAS system integration and flight operations, full lifecycle C5ISR engineering services, cybersecurity and IT/IA innovative solutions and virtual training, simulation & serious game development and implementation. We have established a broad offering of products and capabilities collectively providing decades of experience supporting the full complement of DoD military services, Missile Defense Agency, National Aeronautics and Space Administration, and a variety of other Government organizations and private industry customers.