Senior corporate security systems engineer

Consequential Work. Dedicated People.

About Onebrief
Onebrief builds collaboration and AI-powered workflow software for military planning and operational coordination. Military planning is complex by nature, requiring teams to coordinate information, people, and decisions across systems and locations. Onebrief brings planning, collaboration, simulation, and AI into one connected environment, helping teams test strategies, adapt to changing conditions, and make decisions with greater clarity when the stakes are real. We are a distributed team of builders from military, operational, and technology backgrounds who care deeply about improving how important work gets done. Some team members work remotely, while others work directly alongside customers in operational environments around the world. Founded in 2019, Onebrief is backed by leading investors including General Catalyst, Battery Ventures, Insight Partners, Sapphire Ventures, and Human Capital. Valued at more than $2 billion, we continue to invest in product innovation, AI capabilities, and team growth.

Why This Role Exists
Onebrief is growing, and the systems our employees rely on need to remain secure, resilient, and audit-ready as the company scales. We’re hiring a Corporate Systems Security Engineer to help build and operate the technical security foundations that protect our corporate environment. This is a hands-on security engineering role focused on owning and improving security across endpoints, identity, SaaS applications, browsers, Zero Trust infrastructure, and the broader corporate security stack. You’ll work at the intersection of security engineering, systems configuration, and automation—turning security requirements into technical controls that are measurable, repeatable, and difficult to drift away from. A major focus of this role is reducing manual security operations. Rather than repeatedly collecting the same evidence or discovering configuration drift during an audit, we want to build systems that continuously enforce our security expectations and produce trustworthy evidence of their effectiveness. You’ll work closely with Corporate IT, Security Operations, GRC, and application owners, but your mandate is security: understanding how systems can be abused or misconfigured, establishing secure defaults, and ensuring the controls protecting Onebrief continue to operate as intended.

What You’ll Do
You’ll help own and mature the security systems protecting Onebrief’s corporate environment. Core responsibilities include:

• Own and improve enterprise security technologies across areas such as EDR, SIEM, MDM, Zero Trust, identity, browsers, and SaaS applications, including deployment, configuration, integrations, monitoring, and lifecycle management.
• Establish and enforce secure configuration baselines across corporate systems, continuously identifying configuration drift and building durable mechanisms to remediate it.
• Build API-driven, infrastructure-as-code, or workflow-based automation that connects security systems, eliminates repetitive security work, and makes control enforcement and evidence collection more reliable.
• Partner with Corporate IT and application owners to securely deploy and operate endpoints, applications, and SaaS platforms while maintaining appropriate security boundaries and technical controls.
• Improve security telemetry by integrating corporate systems and applications with centralized monitoring and ensuring the signals necessary to detect vulnerabilities, misconfigurations, and suspicious activity are available and actionable.
• Translate security and compliance requirements—including CMMC 2.0 and NIST-aligned controls—into practical technical implementations that can be continuously validated and supported with defensible evidence.

Minimum Qualifications
4+ years of hands-on experience in security engineering, enterprise security, systems security, or a closely related technical role. Experience securing identity, SaaS, or Zero Trust environments and understanding how configuration decisions affect enterprise security. Experience building security automation using APIs, workflow automation platforms, infrastructure-as-code, scripting, or configuration-management technologies. Experience deploying, administering, or owning endpoint security and detection technologies such as EDR and SIEM platforms, including integrating security telemetry into centralized monitoring. Experience administering MDM or endpoint-management platforms to enforce security configurations, and maintain endpoint baselines. Ability to evaluate technical requirements through a security lens, identify risk in proposed configurations, and work across technical teams to implement practical controls without losing sight of the security objective.

Preferred Qualifications
Experience owning or administering technologies such as CrowdStrike, Zscaler, enterprise MDM, identity providers, SIEM platforms, or comparable enterprise security systems. Experience implementing technical controls aligned with CMMC 2.0, NIST 800-53, CIS STIGs, or similar security frameworks. Experience building integrations between SaaS or security platforms using REST APIs, webhooks, or automation platforms such as Github Actions or Okta Workflows. Experience securing corporate environments in regulated, government, defense, or other high-assurance organizations.

Indicators of Success
This role will evolve as priorities change, but the outcomes below reflect what success typically looks like in the first six months. A successful Corporate Systems Security Engineer will:

• Become a trusted technical owner for key components of Onebrief’s corporate security stack, with clear understanding of their architecture, configuration, integrations, and security posture.
• Reduce configuration drift across corporate endpoints, SaaS applications, identity systems, and security tooling through measurable baselines and automated enforcement.
• Improve the reliability and coverage of security telemetry by integrating critical corporate systems with centralized monitoring and addressing meaningful visibility gaps.
• Replace recurring manual security and compliance processes with automation that improves control consistency and produces reliable, reusable evidence.
• Identify and remediate systemic security weaknesses rather than treating individual findings as isolated configuration issues.
• Improve Onebrief’s ability to demonstrate that corporate security controls are continuously operating as intended, reducing the effort required to prepare for audits and assessments.

Tools, Systems & Technologies
The specific technology stack will continue to evolve. Relevant areas include:

• Endpoint & Detection: EDR (crowdstrike), vulnerability management, SIEM (splunk), endpoint telemetry
• Device Management: MDM (Workspace One), application deployment, configuration profiles, endpoint baselines
• Identity & Access: Identity providers (Okta), SSO, MFA, lifecycle management, conditional access
• Network & Zero Trust: Zero Trust access platforms (Zscaler), secure web gateways, browser security, network security controls
• SaaS Security: Enterprise SaaS administration, configuration management, logging, access controls, API integrations
• Automation: REST APIs, webhooks, no-code/low-code security automation, infrastructure-as-code, configuration management
• Security & Compliance: CMMC 2.0, NIST 800-53, security baselines, continuous control validation, audit evidence

Notice to Third Party Recruitment Agencies
Please note that Onebrief does not accept unsolicited resumes from recruiters or employment agencies. In the absence of an executed Recruitment Services Agreement, there will be no obligation to any referral compensation or recruiter fee. In the event a recruiter or agency submits a resume or candidate without an agreement Onebrief explicitly reserves the right to pursue and hire those candidate(s) without any financial obligation to the recruiter or agency. Any unsolicited resumes, including those submitted to hiring managers, shall be deemed the property of Onebrief.