Senior/Staff/Principal SWE - OT Security Engineering

AppGate is a leader in Zero Trust Network Access (ZTNA) solutions, dedicated to securing critical assets for Fortune 500 enterprises. They are seeking an OT Security Engineer to design and implement secure remote access capabilities for their OT platform, working closely with the CTO and product management team.

Responsibilities:

• Secure Remote Access Platform: Identity-bound, MFA-protected access anchored at the OT DMZ / Purdue Level 3, with session brokering, just-in-time privilege, and policy enforcement designed for industrial environments
• Protocol-Aware Policy Authoring: A Protocol Registry that maps OT protocol names (Modbus TCP, DNP3, IEC 61850, OPC-UA, EtherNet/IP) to port and transport defaults, making policy authoring OT-aware without changing the underlying enforcement model
• Evidence and Audit Baseline: Structured access logs capturing user identity, target, session start/end, and outcome - forwardable to Splunk, Kinesis, Datadog etc. supporting NERC CIP, IEC 62443, NIST SP 800-82, and CMMC audit requirements
• Session Governance: Enforced session recording, keystroke logging, step-up authentication, and dual-authorization approval workflows for regulated and defense environments
• Asset Context Ingestion (Phase 2+): API-based integration with OT visibility platforms (Dragos, Nozomi, Claroty) normalized into policy-ready attributes, without blocking access in the critical path
• Design and implement backend services across AppGate's distributed architecture — Controller, Gateway, and Connector components — with a focus on OT-safe deployment patterns
• Build and maintain REST and gRPC APIs supporting policy evaluation, access control, protocol registry management, and OT-specific system integrations
• Apply Zero Trust principles to remote access for industrial assets, accounting for the safety, uptime, and determinism constraints of OT environments
• Integrate with industrial protocols and OT asset types — PLCs, RTUs, HMIs, historians — running Modbus, DNP3, OPC-UA, Profinet, and EtherNet/IP
• Own features end-to-end, from architecture through production deployment in real customer environments
• (Staff / Principal) Define technical direction, lead architecture reviews, and support hiring as the OT engineering function scales

Requirements:

• Hands-on background building or operating secure remote access systems — VPN, ZTNA, jump servers, privileged access, session brokers, or equivalent
• Direct experience in or with OT / ICS environments — manufacturing, energy, utilities, oil and gas, water, transportation, or defense
• Strong systems programming in Go, Rust, or a comparable language
• Solid networking (TCP/IP, TLS, firewalls) and identity (SAML, OIDC, PKI) fundamentals
• Familiarity with the Purdue Model and IT/OT DMZ design patterns
• Working knowledge of OT protocols: Modbus, DNP3, OPC-UA, EtherNet/IP
• High ownership, end-to-end accountability, comfortable in a small team where you solve problems before they become fires
• Experience with OT/SRA/PAM platforms: Claroty, Dragos, Nozomi, Xona, Cyolo, Dispel, SSH PrivX OT, CyberArk, or BeyondTrust
• Exposure to IEC 62443, NIST SP 800-82, NERC CIP-005/007, or CMMC
• Background in safety-critical, regulated, or compliance-driven environments
• (Staff / Principal) Track record owning platform architecture and mentoring engineering teams