Senior Software Engineer

Core OS is responsible for the foundational technologies that underpin Windows and Windows Server, providing the trusted platform on which customers run their most critical workloads. Our team combines deep systems engineering with modern AI innovation to bring the next generation of intelligent capabilities to enterprise environments.

We are hiring a Senior Software Engineer in CoreOS to help build threat-resistant platform capabilities for Windows Server across on-premises, hybrid, and cloud-connected deployments. This is a hands-on engineering role: you will turn security architecture and threat models into shipping code, implement secure-by-design features, close systemic classes of vulnerabilities, and strengthen the platforms trust boundaries from firmware and boot through the kernel, virtualization, identity, and management surfaces.

You will work on the platforms threat-resistant capabilities and bring secure-by-design and secure-by-default ideas to reality. You will translate evolving threats, security requirements, and customer needs into working software while owning the design and implementation of well-scoped components.

At Microsoft, our mission—to empower every person and every organization on the planet to achieve more—guides how we partner with customers to deliver trusted, impactful solutions. With a growth mindset culture, we innovate responsibly and measure success by shared progress—people, teams, and customers. Join us to do meaningful work that changes the world and helps shape what’s next for everyone.

Responsibilities

• Design and implement the validation framework to test and maintain secure-by-design features with automated test coverage, and fuzzing to catch defects early, and balancing security, reliability, performance, compatibility, and secure servicing. Apply secure defaults, hardening baselines, cryptographic standards, key management, auditability and logging in the components you own.
• Build observability pipelines through telemetry insights, security metrics, and health signals needed to measure how well those controls work in production.
• Contribute to threat modeling and security reviews and build mitigations for high-severity threats and systemic classes of vulnerabilities, validating each mitigation with targeted test cases and regression coverage so fixes hold over time.
• Support security incidents and partner with product, support, field, Artificial Intelligence (AI), and security-adjacent teams to assess impact, deliver containment and remediation fixes, use observability and telemetry to detect and diagnose issues, incorporate real-world attack patterns and operational constraints, and land post-incident hardening improvements.

Qualifications

Required Qualifications

• Bachelors Degree in Computer Science or related technical field AND 4+ years technical engineering experience with coding in languages including, but not limited to, C, C++, C# or Python OR equivalent experience.

Preferred Qualifications

• 6+ years of professional software engineering experience with coding in one or more languages such as C, C++, C#, Python, Rust,, PowerShell or Kusto, including designing automated tests and validation for the software you ship.
• Experience or demonstrated interest in OS fundamentals and/or software and system security.
• Demonstrated experience in confidential computing, using cryptography in a secure way, including sound selection and application of cryptographic primitives, careful key management, and secure protocol design.
• Familiarity with platform security controls such as Secure Boot and Trusted Platform Module (TPM), virtualization-based security (VBS), code integrity, Credential Guard, WDAC/App Control, BitLocker, and Secured-core.
• Understanding of threat modeling and modern attacker techniques (credential theft, lateral movement, privilege escalation, persistence, and supply-chain or build attacks), the corresponding defenses, and how to detect them through security telemetry and observability.

Software Engineering IC4 - The typical base pay range for this role across the U.S. is USD $119,800 - $234,700 per year. There is a different range applicable to specific work locations, within the San Francisco Bay area and New York City metropolitan area, and the base pay range for this role in those locations is USD $160,200 - $261,000 per year.