Penetration Tester III

Washington, DC, us on site Until 8/21/2026 First posted April 22, 2026 Last posted April 22, 2026
Job description

Founded in 1989, SOSi is among the largest private, founder-owned technology and services integrators in the defense and government services industry. We deliver tailored solutions, tested leadership, and trusted results to enable national security missions worldwide.

Overview

SOSi is seeking a Penetration Tester III to support proactive cyber defense activities in alignment with our customer. This role is responsible for conducting penetration testing and red team activities, assessing security posture across enterprise environments, and supporting identification, validation, and reporting of vulnerabilities to improve cyber defense resilience.

Responsibilities

·  Conduct penetration testing across enterprise systems, applications, and network environments

·  Perform red team activities to evaluate security controls and identify exploitable weaknesses

·  Support continuous penetration testing activities to assess evolving threats and vulnerabilities

·  Conduct testing of IoT, mobile, and cloud environments

·  Support High Value Asset (HVA) security assessments

·  Apply testing methodologies and frameworks including MITRE ATT&CK, OSSTMM, OWASP, NIST, PTES, and ISSAF

·  Identify, document, validate, and report vulnerabilities and recommended remediation actions

·  Support cyber defense operations through coordination with security engineering, vulnerability management, and incident response teams

 

  • Experience:
    • Five (5) to seven (7) years of penetration testing experience
    • Management or team lead experience
    • Experience performing continuous penetration testing
    • Experience conducting red team operations
    • Experience performing IoT, mobile, and cloud penetration testing
    • Experience supporting High Value Asset (HVA) assessments
    • Experience applying MITRE ATT&CK, OSSTMM, OWASP, NIST, PTES, and ISSAF methodologies
  • Education:
    • Bachelor’s Degree
  • Certifications:
    Required:
    • GPEN or GXPN
    • CISA AES HVA Lead or Technical Lead, or ability to obtain
      • Plus one of the following:
      • GRTP
      • CRTL
      • OSCP
      • CRTP
      • CMWAPT
      • CEPT
      • CPT
      • LPT
         
  • Clearance/Suitability: Secret (active)

Work Environment

  • Normal office conditions with potential to perform duties in deployed locations.
  • Core hours of operation are Monday through Friday, 0600 – 1700.
  • May be requested to work evenings and weekends to meet program and contract needs.

Working at SOSi

All interested individuals will receive consideration and will not be discriminated against for any reason.

About this role

Summary

Conduct penetration testing, red team activities, and vulnerability assessments for enterprise security.

Job title

Penetration Tester III

Experience level

5-7 years

Industry

cybersecurity

Location requirements

Washington, DC, US, on-site, with travel to deployed locations allowed

Salary

Not specified

Management role

Yes

Skills & keywords

Required skills

penetration testingred teamIoTmobilecloudMITRE ATT&CKOSSTMMOWASPNISTPTESISSAFGPENGXPNCISA

Preferred skills

None specified

Specializations

penetration testingred teamcyber defensecloud securityIoT
Locations

Structured locations inferred from the posting.

Washington, DC, USA

On-site City