Jobs in the United States

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Added 2 hours ago
RC
Part Time Software Platform Engineer Co-Op (Remote)
RTX Corporation
richardson, TX
- Part-time
Raytheon is hiring SW Platform Engineer Co-Ops as a part of the Raytheon Cooperative Education Program (Co‑op). This is a part-time, remote role targeting senior or postgraduate students…
Added 6 hours ago
BA
Full Stack Developer, Mid
Booz Allen Hamilton
Aurora, CO
- $69,400 to $158,000 USD / year
Active TS/SCI clearance; willingness to take a polygraph exam
Added 6 hours ago
BA
Full Stack Developer, Mid
Booz Allen Hamilton
Aurora, CO
- $69,400 to $158,000 USD / year
Active TS/SCI clearance; willingness to take a polygraph exam
Added 10 hours ago
RC
Part Time Software Platform Engineer Co-Op (Remote)
RTX Corporation
aurora, CO
- Part-time
Raytheon is hiring SW Platform Engineer Co-Ops as a part of the Raytheon Cooperative Education Program (Co‑op). This is a part-time, remote role targeting senior or postgraduate students…
Added 20 hours ago
Product Security Engineer (Senior)
The Boeing Company
Seal Beach, CA · El Segundo, CA
The Boeing Company is seeking a Senior Product Security Engineer to join the Boeing team in Seal Beach, CA or El Segundo, CA. This position will focus on supporting a proprietary program…
Added 22 hours ago
Senior DevOps Engineer
Resource Management Concepts, Inc.
Charleston, SC
The engineer will work closely with software developers to establish consistent environments and move services into reliable, scalable deployments. Candidates should understand how cloud…
Added 22 hours ago
Senior Database Engineer
Resource Management Concepts, Inc.
Charleston, SC
Active TS/SCI clearance with the ability to obtain a CI polygraph.
Added 1 day ago
Lead Cyber Security Engineer
The MITRE Corporation
Fort Meade, MD
Active TS/SCI clearance with CI polygraph required
Added 1 day ago
Platform DevOps Engineer, Senior
Booz Allen Hamilton_United States
Chantilly, VA
…eligibility requirements for access to classified information; TS/SCI clearance with polygraph is…
Added 1 day ago
Senior Software Engineer
2HB Incorporated
Annapolis Junction, MD
This is a full-time position, and requires a TS/SCI/Full Scope Polygraph Clearance.
Added 1 day ago
Principal Information System Security Officer
Clarity Innovations
Columbia, MD
U.S. citizen able to obtain and maintain a TS/SCI clearance with CI polygraph, as longer-term duties include cross-environment coverage
Added 1 day ago
SS
Systems Engineer
Space Systems Integr
Colorado Springs, CO
- $110,000 to $135,000 USD / year
…our customers' technical challenges. SSI is seeking a Systems Engineer for a role in Colorado Springs, CO. You will provide systems engineering and technical integration support across…
Added 1 day ago
Cyber Automation Engineer
Booz Allen Hamilton_United States
Alexandria, VA · St. Louis, MO
…eligibility requirements for access to classified information; TS/SCI clearance with polygraph is…
Added 2 days ago
Senior DevOps Engineer
Bigbear.ai
Washington
TS/SCI clearance with current CI polygraph (required).
Added 2 days ago
Software Development Engineer (TS/SCI)
Vantor Services Inc.
Herndon, VA
US citizenship and a current TS/SCI clearance (with willingness to get a CI Polygraph).
Added 2 days ago
Systems Engineer
Radiance Technologies, Inc.
Beavercreek, OH
Radiance Technologies is an employee-owned company with benefits that are unmatched by most companies in the Dayton OH area. Employee ownership, generous 401K, full…
Added 2 days ago
Systems Software Engineer
DAn Solutions
Washington, DC
REQUIRES AN ACTIVE/EXISTING TS/SCI WITH CI POLYGRAPH
Added 2 days ago
Senior DevOps Engineer – Cloud Infrastructure & Core Services
DAn Solutions
Washington, DC
REQUIRES AN ACTIVE/EXISTING TS/SCI WITH CI POLYGRAPH
Added 2 days ago
DevSecOps Engineer - TS/SCI with Polygraph
GD Information Technology, Inc.
United States
Transform technology into opportunity as a DevSecOps Engineer at GDIT. Shape what’s next for mission-critical government projects while shaping what’s next for your engineering career.
Added 2 days ago
Machine Learning Engineer (TS/SCI)
Vantor Services Inc.
Herndon, VA
US citizenship and a current TS/SCI clearance (with willingness to get a CI Polygraph).
Added 2 days ago
A
DevOps Engineer
AnaVation
Chantilly, VA
- $92,905.44 to $218,324.12 USD / year
This position requires an active Top Secret (TS) clearance and the ability to obtain SCI access with a CI polygraph. This position is on-site in Chantilly, VA.
Added 3 days ago
Cleared - Cyber Security Engineer
Noblis
Bethesda, MD
Noblis is seeking a cleared Cyber Security Engineer to support our customer in Bethesda, MD. SETA
Added 3 days ago
M
Senior Systems Engineer
Markon
McLean, VA
- $155,000 to $185,000 USD / year
An active TS/SCI clearance with Full Scope Polygraph (FSP) is required to be considered for this role.
Added 3 days ago
DevOps Engineer
CACI International
Denver, CO
Minimum Clearance Required to Start: TS/SCI with Polygraph
Added 3 days ago
Engineer Principal – Embedded Software
BAE Systems
Boulder, CO · Westminster, CO · Broomfield, CO
…Space & Mission Systems (SMS) is looking to expand our team with a talented and energetic software engineer focused on delivering high-quality, embedded satellite software and associated…

Cornerstone Defense

Senior Information Systems Security Engineer

United States

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Job details

Apply by: Apr 1, 2027
Experience: 7+ years cybersecurity/ISSE experience designing, implementing, and assessing security controls
Posting language: English
Posted: Apr 1, 2026

Original job description

Senior Information Systems Security Engineer

TS/SCI with polygraph

Reston, VA

Company Overview:

Cornerstone Defense is the Employer of Choice within the Intelligence, Defense, and Space communities of the U.S. Government. Realizing early on that our most prized assets are our employees, we continually focus our attention on improving the overall work/life experience they have supporting the mission. Our Team is pushed every day to use their industry leading knowledge to provide end-to-end solutions to combat our nation’s toughest and most secure problems. If you are looking for a place to not only be professionally challenged, but encouraged and supported by a company that cares, don’t look any further than Cornerstone Defense.

Benefits Overview:

Cornerstone Defense offers a very comprehensive benefits package including, but not limited to: Medical, Dental and Vision Plans * Generous PTO Policy * 401(k) * HSA and FSA options * Life and Disability Insurance * Tuition Reimbursement and Training * Perks at Work Discount Program * Referral Program * Leads Generation Program * CollegeAmerica 529 * Fitness Reimbursement Program * Travel Assistance * Norton Lifelock Benefit Solutions * Life Planning Financial & Legal Services *

We are seeking a highly skilled, hands‑on Senior Information Systems Security Engineer (ISSE) to secure mission‑critical systems across hybrid, cloud, and air‑gapped environments. The ideal candidate brings deep technical expertise in RMF, STIG compliance, vulnerability scanning, continuous monitoring, and secure system engineering - someone who is actively involved in building and configuring secure solutions rather than simply reviewing them. In this role, you will design, engineer, assess, and sustain security controls across complex system architectures, ensuring compliance, operational readiness, and mission resilience.

What you’ll do:

Engineer, implement, and manage security solutions (firewalls, IDS/IPS, endpoint protection, encryption)
Perform security assessments across systems, applications, and networks
Implement, validate, and maintain RMF NIST 800‑53 controls across on‑prem, cloud, and air‑gapped systems
Conduct STIG checks, hardening, and secure configuration updates for OS, applications, network devices, and cloud resources
Run ACAS/Tenable scans, analyze vulnerabilities, and drive remediation with engineering teams
Configure log ingestion, parsing, and data flows into SIEM platforms (Splunk), and build dashboards and alerts
Monitor network traffic, logs, and events to detect anomalies and security threats
Conduct incident investigations and provide technical recommendations for mitigation
Maintain and enhance incident response plans and continuous monitoring procedures
Engineer, configure, and modify secure system and network baselines
Analyze and troubleshoot network protocols, packet flows, and configuration issues
Produce RMF artifacts, POA&Ms, scan reports, dashboards, and security documentation
Collaborate with DevSecOps, system engineering, IT, and development teams to embed security into the lifecycle
Write user stories, define security acceptance criteria, and support regression testing
Perform system assessments and security engineering within air‑gapped and restricted networks
Support ongoing continuous monitoring activities and security control reviews

What you’ll need

7+ years cybersecurity/ISSE experience designing, implementing, and assessing security controls
Strong experience with RMF, NIST 800‑53, STIGs, ICD 503, FISMA, FedRAMP
SIEM experience, including log configuration, dashboards, and analytics (Splunk preferred)
Hands‑on ACAS/Tenable vulnerability scanning and analysis
Cloud security experience (AWS/Azure/GovCloud) in IL5–IL6 environments
Strong understanding of network protocols, OS internals, and infrastructure security
Skilled in incident response and forensic analysis
Experience with tools such as Fortify, Acunetix, and Prisma Cloud
Experience configuring/modifying secure system and network baselines
Familiarity with agile workflows, user stories, and regression testing
Experience working in air‑gapped or disconnected environments
Strong communication skills for both technical and non‑technical audiences
CISSP or DoD 8140‑approved certification
Active TS/SCI with CI poly

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More about this job

Skills

Regulatory compliance
Coordinate security
IDS
IPS
Symantec Endpoint Protection
Splunk
Security threats
Incident response
Quality assurance procedures
Troubleshoot
Documentation
Monitor activities
Cybersecurity
AWS
Microsoft Azure
Communication skills
CISSP

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