OS Implementation & Systems

Master operating system internals, security mechanisms, and system hardening for Linux and Windows environments.

Linux Fundamentals
Windows Internals
System Security
Kernel Security

Linux Fundamentals & Security

Understanding Linux system architecture, security mechanisms, and hardening techniques.

Linux System Architecture

Core components and structure of the Linux operating system.

Key Components:

  • • Kernel - Core system component managing hardware and processes
  • • System calls - Interface between user space and kernel
  • • Process management - PID, scheduling, memory management
  • • File system - VFS, inodes, permissions, mount points
  • • Device drivers - Hardware abstraction layer
  • • System libraries - glibc, system utilities

Linux Security Mechanisms

Built-in security features and access control mechanisms.

Security Features:

  • • File permissions (rwx) and ownership
  • • SUID/SGID bits and sticky bits
  • • SELinux and AppArmor mandatory access control
  • • Capabilities system for fine-grained privileges
  • • Namespaces for process isolation
  • • Control groups (cgroups) for resource limits

Windows Internals & Security

Understanding Windows system architecture, security model, and internal mechanisms.

Windows System Architecture

Core components and structure of the Windows operating system.

System Components:

  • • Hardware Abstraction Layer (HAL)
  • • Windows Kernel (ntoskrnl.exe)
  • • Executive Services
  • • System Services and Win32 API
  • • User Mode Applications

Process Management:

  • • Process and Thread objects
  • • Virtual Memory Management
  • • I/O Manager and Device Drivers
  • • Registry and Configuration
  • • Security Reference Monitor

Windows Security Model

Windows security mechanisms and access control systems.

Security Components:

  • • Security Reference Monitor (SRM)
  • • Local Security Authority (LSA)
  • • Security Account Manager (SAM)
  • • Active Directory (AD) integration
  • • Windows Defender and security features

Access Control:

  • • Discretionary Access Control (DAC)
  • • Mandatory Access Control (MAC)
  • • Role-Based Access Control (RBAC)
  • • Security tokens and privileges
  • • User Account Control (UAC)

System Hardening & Security

Implementing security controls and hardening measures for operating systems.

Linux Hardening

Hardening Steps:

  • • Remove unnecessary services and packages
  • • Configure firewall rules (iptables/nftables)
  • • Implement file system security
  • • Configure user and group permissions
  • • Enable and configure SELinux/AppArmor
  • • Regular security updates and patches

Windows Hardening

Hardening Steps:

  • • Configure Group Policy settings
  • • Enable Windows Defender features
  • • Configure firewall and network security
  • • Implement least privilege access
  • • Configure BitLocker encryption
  • • Regular security updates and patches

Monitoring & Detection

Monitoring Areas:

  • • System logs and event monitoring
  • • Process and service monitoring
  • • File system integrity checking
  • • Network traffic analysis
  • • User activity monitoring
  • • Security event correlation

Kernel Security & Exploitation

Understanding kernel-level security mechanisms and common exploitation techniques.

Kernel Exploitation

Common kernel-level vulnerabilities and exploitation techniques.

Common Vulnerabilities:

  • • Buffer overflows in kernel drivers
  • • Use-after-free vulnerabilities
  • • Integer overflow and underflow
  • • Race conditions and TOCTOU
  • • Privilege escalation through kernel bugs

Exploitation Techniques:

  • • Kernel heap spraying
  • • Return-oriented programming (ROP)
  • • Kernel module injection
  • • Memory corruption techniques
  • • Bypassing security mitigations

Kernel Security Mitigations

Security mechanisms to protect against kernel-level attacks.

Linux Mitigations:

  • • Kernel Address Space Layout Randomization (KASLR)
  • • Stack canaries and stack protection
  • • Control Flow Integrity (CFI)
  • • Kernel module signing
  • • SELinux and AppArmor kernel integration

Windows Mitigations:

  • • Kernel Address Space Layout Randomization (KASLR)
  • • Data Execution Prevention (DEP)
  • • Control Flow Guard (CFG)
  • • Driver signature enforcement
  • • Secure Boot and Trusted Boot