Junior Vulnerability Researcher (5G & Protocol Security)

CACI International • Florham Park, NJ

23h

About The Position

We are seeking a Vulnerability Researcher to join our 5G security team, focusing on protocol analysis and firmware reverse engineering. This role is for a practitioner with a strong systems background who is ready to take ownership of research tasks within complex telecommunications stacks. You will work as part of a high-performing group, identifying security flaws in 3GPP protocols and proprietary telecom binaries while developing the automated tooling necessary to secure national mobile infrastructure.

Requirements

• An active Top Secret clearance.
• 3–5 years of professional experience in software exploitation, reverse engineering, or protocol development.
• Strong proficiency in C/C++ and scripting experience in Python3.
• Working knowledge of 4G/5G architecture and networking protocols (TCP/IP, SCTP, HTTP/2).
• Experience with disassembly tools such as IDA Pro, Ghidra, or Binary Ninja.
• Foundational understanding of binary analysis and memory corruption primitives.
• Demonstrated ability to conduct independent technical research and analyze complex software systems.

Nice To Haves

• An active SCI clearance.
• Experience with software-defined radio (SDR) or cellular testing equipment.
• Familiarity with Linux-based telecom network functions.
• Participation in security research projects or CTFs with a focus on networking or pwnable challenges.

Responsibilities

• Execute research into 3GPP protocols (NGAP, GTP, etc.) to identify crashes and logic flaws using stateful fuzzing techniques.
• Perform static and dynamic analysis on compiled telecom binaries and firmware to understand undocumented protocol logic.
• Support the development of custom Python3 scripts for protocol decoding and automating analysis of "closed-box" systems.
• Assist in mapping state machines within 5G session management flows using symbolic or concolic execution tools.
• Analyze signaling and data plane components to identify potential attack surfaces in 5G Core and RAN environments.
• Use debugging tools and packet analysis software (e.g., Wireshark) to inspect protocol traffic and hardware state.
• Document research findings and contribute to the development of technical security reports.

Benefits

• Our employees value the flexibility at CACI that allows them to balance quality work and their personal lives.
• We offer competitive compensation, benefits and learning and development opportunities.
• Our broad and competitive mix of benefits options is designed to support and protect employees and their families.
• At CACI, you will receive comprehensive benefits such as; healthcare, wellness, financial, retirement, family support, continuing education, and time off benefits.

What This Job Offers

• Job Type: Full-time
• Career Level: Entry Level
• Education Level: No Education Listed
• Number of Employees: 5,001-10,000 employees