Senior 5G Security Engineer - Protocol & Reverse-Engineering

CACI; United States; On-site; USD 113,000 - 238,000; Full time

Job summary

CACI is seeking a Senior Penetration Engineer (5G & Protocol Security) to lead advanced security assessments of telecom systems. You will reverse‑engineer closed binaries, develop stateful fuzzers, and map complex 5G authentication flows while reporting actionable findings to engineering teams.

The role emphasizes deep protocol knowledge, hands-on binary analysis, and tool development in Python/C++. A US citizenship and ability to obtain a security clearance are required, with up to 10% travel

Qualifications

• 7+ years of vulnerability research, protocol analysis, or reverse engineering.
• Deep understanding of 5G/4G architecture and 3GPP security standards.
• Knowledge of telecom protocol stacks, signaling, management and data plane components.
• Experience with Linux kernel internals or RTOS used in telecom hardware.
• Hands-on experience with disassembly/decompilation tools and hardware debugging.
• US citizenship and ability to obtain/maintain a security clearance.

Responsibilities

• Investigate edge-case behaviors and protocol signaling to reveal attack surfaces in proprietary telecom and embedded systems.
• Reverse-engineer 5G baseband firmware and NF binaries where source code is unavailable.
• Develop custom Python3 tools to automate protocol decoding, firmware unpacking, and analysis workflows.
• Develop and deploy custom stateful fuzzers for 3GPP protocols to identify crashes in the 5G Core.
• Use concolic and symbolic execution to map state machines and uncover logic flaws in session management and authentication flows.
• Create PoC exploits for vulnerabilities in components such as AMF, SMF, or UPF.
• Document findings clearly and translate technical protocol complexity into actionable reports.

Skills

5G protocol security

Reverse engineering

Python

C/C++

Disassembly tools

Hardware debugging

Tools

IDA Pro

Ghidra

Binary Ninja

JTAG/UART

Job description

CACI is seeking a Senior Penetration Engineer (5G & Protocol Security) to lead advanced security assessments of telecom systems. You will reverse‑engineer closed binaries, develop stateful fuzzers, and map complex 5G authentication flows while reporting actionable findings to engineering teams.

The role emphasizes deep protocol knowledge, hands-on binary analysis, and tool development in Python/C++. A US citizenship and ability to obtain a security clearance are required, with up to 10% travel