Principal Kernel Engineer

Summary

Join Halcyon, a leading anti-ransomware platform developer, as a Principal Kernel Engineer. You will be instrumental in designing and enhancing our Windows kernel components for ransomware prevention, detection, and response. This role demands extensive experience with Windows OS internals and a proven ability to deliver robust, secure, high-performance drivers. Collaborate with senior engineers and product teams, mentor other developers, and contribute to the evolution of our kernel architecture. The position requires deep expertise in Windows kernel development, mastery of C++, and expert-level debugging skills. Halcyon offers a competitive salary and benefits package, including comprehensive healthcare, 401k, disability and life insurance, flexible PTO, parental leave, and generous equity.

Requirements

• 15+ years of exclusive, professional Windows kernel development — deep understanding of NT internals, OS architecture, and low-level subsystems
• Proven track record of shipping multiple production-quality Windows drivers (file system, networking, or security-related) in commercial products
• Mastery of C++ in kernel-mode and user-mode, including multithreading, synchronization primitives, IRQL management, and lock-free programming
• Expert-level debugging skills — WinDbg, KD, crash dump analysis, race condition resolution
• Strong knowledge of Win32 APIs , kernel security boundaries, and performance tuning at the OS level
• Experience designing for stability, security, and performance
• Exceptional communication skills and ability to collaborate across engineering and product teams

Responsibilities

• Apply deep Windows kernel expertise to develop and optimize kernel-mode components that power Halcyon’s ransomware prevention and detection capabilities
• Contribute to the design and implementation of secure, high-performance Windows drivers (e.g., file system mini-filters, network callout drivers, process/thread monitoring)
• Investigate, debug, and resolve complex kernel-level issues — from race conditions to memory corruption — using WinDbg, crash dump analysis, and advanced debugging techniques
• Help set technical direction for kernel development across the Windows agent, influencing architecture and performance trade-offs
• Mentor and guide other engineers in kernel-mode development best practices and secure coding patterns

Preferred Qualifications

• Experience with Rust in systems programming, or a strong desire and capacity to learn quickly
• Familiarity with Portable Executable (PE) format and reverse engineering tools
• Hands-on experience with Windows Mini-Filter drivers, Windows Filter Platform (WFP), or kernel-based process protection mechanisms
• Exposure to Rust/C++ interoperability in production systems
• Background in endpoint security, EDR, or other OS-level security products

Benefits

• Comprehensive healthcare (medical, dental, and vision) with premiums paid in full for employees and dependents
• 401k plan with a generous employer contribution
• Short and long-term disability coverage, basic life and AD&D insurance plans
• Medical and dependent care FSA options
• Flexible PTO policy
• Parental leave
• Generous equity offering