Countermeasures Engineer

Location: Shiloh, IL

Time Type: Full time

Job Description

Defend the Nation's Networks Through Innovation and Advanced Cyber Engineering

Join the front lines of national defense as a Countermeasures Engineer supporting the GSM-O II program. You'll provide critical network operations and cyber defense support to the Defense Information Systems Agency (DISA), protecting DoD and Combatant Command networks from the world's most sophisticated adversaries. 

Your Mission

 Countermeasure Development & Deployment:

• Design and deploy innovative, custom countermeasures to neutralize advanced threats and expose adversary activities on Classified terrain.

• Develop cutting-edge malware detection capabilities tailored to emerging threat actor techniques 

• Continuously evaluate countermeasure effectiveness against evolving Advanced Persistent Threats (APTs) and adjust strategies in real-time 

• Apply Detection-as-a-Code principles to create scalable, version-controlled security solutions 

Automation & Engineering Excellence: 

• Architect and build automated cybersecurity solutions that deliver enterprise-wide protection at scale 

• Develop custom integrations, data correlation engines, and processing pipelines to reduce cyber risk across the DoD & Classified terrain. 

• Conduct agile development and maintenance of automation scripts and tools using modern DevSecOps practices 

• Serve as a Subject Matter Expert (SME) for the automation team, mentoring others and driving technical innovation 

Threat Intelligence & Situational Awareness: 

• Maintain continuous awareness of the cyber threat landscape by analyzing DoD, Intelligence Community, and open-source intelligence reporting 

• Identify new vulnerabilities, malware families, and threat actor TTPs that could impact mission-critical networks 

• Translate threat intelligence into actionable defensive measures and detection capabilities 

• Collaborate with DISA, mission partners, and Combatant Commands to enhance collective defense postur 

What You Bring

Required Qualifications:

• Active DoD Top-Secret Clearance 

• Bachelor's degree in Computer Science, Cybersecurity, Computer Engineering, or related field with 8+ years of hands-on experience (or equivalent combination of education and experience)

• DoD 8570 IAT Level II certification (Security+ CE or equivalent) , CSSP-A certification required within 180 days

• Strong programming proficiency in at least one modern language: Python, Java, Ruby, or C++

• Proven experience developing custom malware detection capabilities

Advanced understanding of:

• TCP/IP, network protocols, ports, and traffic flow analysis

• System administration across multiple platforms

• OSI model and defense-in-depth security architecture

• Common security elements and enterprise security technologies

• Deep knowledge of threat actor lifecycle, attack vectors, exploitation methods, and intrusion set Tactics, Techniques, and Procedures (TTPs)

• UNIX/Linux administrative skills

Highly Desired Experience:

• Direct experience with DISA and DoD network environments

• Proven track record countering APTs and nation-state threats targeting DoD networks

• Advanced cybersecurity analytics development and implementation

• DevSecOps experience developing and supporting secure development environments

• Automation expertise using Bash, Python, PowerShell, or other scripting languages

• Linux and Windows system administration in cloud or virtualized environments (AWS, Azure, VMware)

• API development and integration experience

• Proficiency with security tools: Git, Sigma, Yara, Snort, Suricata

• Hands-on malware analysis using reverse engineering techniques

• Advanced certifications: GREM, OSCP, GCFA, CISSP, CASP, or GIAC

Why This Role Matters

As a Countermeasures Engineer, you'll be a force multiplier for national defense. Your innovative solutions will protect critical DoD infrastructure, support warfighter operations, and defend against nation-state cyber campaigns. You'll work alongside elite cyber professionals, engage directly with Intelligence Community partners, and see the immediate impact of your work on national security.

If you're looking for comfort, keep scrolling. At Leidos, we outthink, outbuild, and outpace the status quo — because the mission demands it. We're not hiring followers. We're recruiting the ones who disrupt, provoke, and refuse to fail. Step 10 is ancient history. We're already at step 30 — and moving faster than anyone else dares.

Original Posting:

September 29, 2026

Pay Range:

Pay Range $87,100.00 - $157,450.00

The Leidos pay range for this job level 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 the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law.