Operating System Security

Operating system security is the discipline of designing, implementing, and operating controls that protect the OS from malware, privilege escalation, rootkits, and misconfigurations. It spans kernel hardening, driver security, and user-space isolation, with a defense-in-depth approach that layers authentication, access control, encryption, and auditing. Core mechanisms include memory protection, process isolation, and proper privilege separation, supported by a trusted boot sequence (secure boot) and hardware-backed roots of trust (TPM, HSM). Security models such as Discretionary Access Control (DAC) and Mandatory Access Control (MAC) govern permissions; capability-based models can further reduce risk. Regular patching and vulnerability management are essential to close known weaknesses, while secure development practices, code signing, and reproducible builds reduce supply-chain risk. Attack surfaces include the kernel, drivers, and system services; mitigations focus on least-privilege execution, sandboxing, and virtualization/containerization to limit blast radii. Observability through logging, auditing, and telemetry enables detection and incident response. The OS security posture must adapt to the threat landscape, hardware capabilities, and deployment context (bare metal, virtualized, or cloud).