Security Engineer - Arlington, VA

Position Description & Qualifications

Serco is seeking a Security Engineer to support the Army PPB BOS program. In this role, you will serve as a hands-on cybersecurity professional responsible for protecting mission-critical Army systems and infrastructure. You will apply your expertise across security operations, threat hunting, system hardening, vulnerability remediation, cloud security, and security automation to strengthen the cyber defense posture of critical Army mission systems.

This position is primarily focused on hands-on cybersecurity engineering and operations. Successful candidates will have direct experience implementing, operating, troubleshooting, and improving cybersecurity technologies and controls. While familiarity with RMF documentation, compliance processes, and assessment activities is valuable, the primary focus of this role is technical execution, security engineering, threat detection, incident response, and system defense.

Serco supports the U.S. Army through the Planning, Programming, Budgeting, and Execution Business Operating System (PPB BOS) program. Our team delivers mission-focused technology and cybersecurity solutions that help maintain secure, resilient, and compliant systems supporting Army operations and decision-making.

Candidates must possess an interim or active DoD Secret security clearance. Additionally, candidates must reside within the Washington, DC, Maryland, or Virginia (DMV) area and be willing to work onsite at the Pentagon up to 80% of the time.

In this role, you will:

- Lead the design, implementation, hardening, and sustainment of cybersecurity capabilities across Linux, Windows, enterprise networks, and cloud-based infrastructures (AWS).
- Partner directly with system administrators, software developers, engineers, and government customers to translate technical risk analysis into practical, hands-on remediation and architecture improvements.
- Actively triage and contain threats using EDR/endpoint protection platforms (e.g., CrowdStrike, Microsoft Defender, Trellix/AESS/HBSS). Analyze process trees, decode malicious payloads (e.g., encoded PowerShell), and isolate compromised endpoints directly from the console.
- Write custom SIEM queries (KQL or SPL) from scratch to hunt for advanced persistent threats mapped to the MITRE ATT&CK framework. Pivot through raw network, host, and cloud logs without relying on pre-built dashboards or natural language generators.
- Go beyond simply running ACAS/Nessus scans and tracking POA&Ms. Perform technical risk analysis and work alongside engineering teams to apply patches, enforce DISA STIGs, configure Group Policy Objects (GPOs), and modify system configurations across Windows and Linux hosts.
- Build and maintain custom Python, Bash, or PowerShell scripts to automate incident triage, STIG/control validation, data enrichment, and containment actions. Interact with REST APIs, handle pagination, parse JSON output, and integrate security checks into CI/CD pipelines.
- Implement and enforce technical security controls within AWS and containerized/Kubernetes environments, including IAM least-privilege policies, VPC security groups, GuardDuty/CloudTrail log analysis, and container vulnerability scanning.

To be successful in this role, you will have:

- An interim or active DoD Secret security clearance. U.S. Citizenship.

- Bachelor’s degree in Computer Science, Cybersecurity, or a related technical field.
- 5 years of cybersecurity engineering, cyber operations, information security experience, or related experience.
- An active CompTIA Security+ CE certification or equivalent DoD 8140/8570 baseline certification.
- Demonstrated hands-on experience administering, securing, and troubleshooting Linux, Windows, enterprise networking, and cloud-based infrastructures.
- Proven experience applying the Army RMF process, NIST cybersecurity standards (SP 800-53), DISA STIGs, and vulnerability management tools (ACAS/Nessus) from an engineering implementation and technical risk analysis perspective—developing practical remediation solutions and automating security checks.

Additional desired qualifications:

- Ability to write operational scripts from scratch (Python, PowerShell, or Bash). Modifying existing scripts or relying solely on GUI tools is insufficient.
- Proven ability to manually analyze PCAPs, Windows Event Logs, Linux audit logs, and AWS CloudTrail data to reconstruct security events.
- Ability to troubleshoot broken applications or services after applying DISA STIGs or security patches without simply disabling security controls,
- Hands-on experience supporting and securing cloud architectures, specifically within AWS environments (EC2, VPC, IAM, S3, CloudWatch, GuardDuty).
- Experience integrating security into the Software Development Life Cycle (SDLC), using version control software (Git, GitHub/GitLab), and managing technical workflows in ticket-tracking systems (Jira, ServiceNow).
- Technical experience deploying, configuring, and sustaining ACAS and AESS (HBSS/Trellix) across enterprise enclaves to support A&A and continuous monitoring processes.
- Knowledge of Army PPB BOS (Planning, Programming, Budgeting, and Execution Business Operating System) financial processes and experience collaborating with Army stakeholders, Authorizing Officials (AOs), and Security Control Assessors (SCAs).

If you are interested in working with a dedicated Serco team, then submit your application now for immediate consideration. It only takes a few minutes!

Company Overview

Serco Inc. (Serco) is the Americas division of Serco Group, plc. In North America, Serco’s 9,000+ employees strive to make an impact every day across 100+ sites in the areas of Defense, Citizen Services, and Transportation. We help our clients deliver vital services more efficiently while increasing the satisfaction of their end customers. Serco serves every branch of the U.S. military, numerous U.S. Federal civilian agencies, the Intelligence Community, the Canadian government, state, provincial and local governments, and commercial clients. While your place may look a little different depending on your role, we know you will find yours here. Wherever you work and whatever you do, we invite you to discover your place in our world. Serco is a place you can count on and where you can make an impact because every contribution matters.

To review Serco benefits please visit: https://careers.serco-na.com/us/en/what-we-offer . If you require an accommodation with the application process please email: [email protected] or call the HR Service Desk at 800-628-6458, option 1. Please note, due to EEOC/OFCCP compliance, Serco is unable to accept resumes by email.

Candidates may be asked to present proof of identity during the selection process. If requested, this will require presentation of a government-issued I.D. (with photo) with name and address that match the information entered on the application. Serco will not take possession of or retain/store the information provided as proof of identity. For more information on how Serco uses your information, please see our Applicant Privacy Policy and Notice.

Serco does not accept unsolicited resumes through or from search firms or staffing agencies without being a contracted approved vendor. All unsolicited resumes will be considered the property of Serco and will not be obligated to pay a placement or contract fee. If you are interested in becoming an approved vendor at Serco, please email [email protected] .

Serco is an equal opportunity employer. We evaluate qualified applicants without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, veteran status, and other legally protected characteristics.

Pay Transparency

Our Total Rewards package includes competitive pay, performance-based incentives, and benefits that promote well-being and work-life balance—so you can thrive both professionally and personally. Eligible employees also gain access to a wide range of benefits from comprehensive health coverage and health savings accounts to retirement plans, life and disability insurance, and time-off programs that support work-life balance. Program availability may vary based on factors such as contract type, location, hire date, and applicable collective bargaining agreements.

Salary range: The range for this position can be found at the top of this posting. This range is provided as a general guideline and represents a good faith estimate across all experience levels. Actual base salary will be determined by a variety of factors, including but not limited to, the scope of the role, relevant experience, job-related knowledge, education and training, key skills, and geographic market considerations. For roles available in multiple states, the range may vary to reflect differences in local labor markets. In addition to base salary, eligible positions may include other forms of compensation such as annual bonuses or long-term incentive opportunities.
Benefits – Comprehensible benefits for full-time employees (part-time employees receive a limited package tailored to their role):

Medical, dental, and vision insurance
Robust vacation and sick leave benefits, and flexible work arrangements where permitted by role or contract
401(k) plan that includes employer matching funds
Tuition reimbursement program
Life insurance and disability coverage
Optional coverages that can be purchased, including pet insurance, home and auto insurance, additional life and accident insurance, critical illness insurance, group legal, ID theft protection
Birth, adoption, parental leave benefits
Employee Assistance Plan

To review all Serco benefits please visit: https://careers.serco-na.com/us/en/about-us .

Serco complies with all applicable state and local leave laws, including providing time off under the Colorado Healthy Families and Workplaces Act for eligible Colorado residents, in alignment with our policies and benefit plans. The application window for this position is for no more than 60 days. We encourage candidates to apply promptly after the posting date, as the position may close earlier if filled or if the application volume exceeds expectations. Please submit applications exclusively through Serco’s external (or internal) career site. If an applicant has any concerns with job posting compliance, please send an email to: [email protected] .