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A comprehensive, 12-module engineering course establishing deep mastery of Linux operating system security: kernel architecture, permissions, process isolation, systemd hardening, host firewalls, authentication, auditd logging, capabilities, and incident triage.
Explore the core architecture of the Linux operating system: the hardware kernel/user-space boundary (Ring 0 vs Ring 3), system call dispatch, virtual filesystems (/proc, /sys, /dev), shell execution dynamics, ELF binaries, and the host attack surface.
Master Linux identity primitives: numeric UIDs and GIDs, root authority, /etc/passwd and /etc/shadow architecture, modern password hashing algorithms, dedicated service accounts, non-login shells, and account lifecycle management.
Deconstruct standard Discretionary Access Control (DAC): owner, group, and other permission triples in octal and symbolic modes, directory traversal mechanics, creation umask baselines, special permission bits (SUID, SGID, sticky), and fine-grained POSIX ACLs.
Examine Linux process execution dynamics: the fork() and execve() lifecycle, PID/PPID hierarchy, kernel process states, signal handling (SIGTERM vs uncatchable SIGKILL/SIGSTOP), forensic inspection via procfs, process tree hunting, and virtual memory layout.
Deconstruct modern system initialization and daemon management with systemd. Learn service unit syntax, least-privilege daemon execution (User=, DynamicUser=), systemd timers vs legacy cron, built-in namespace sandboxing directives, and hunting rogue persistence.
Focus on Linux host security: interface states and promiscuous sniffing flags, listening sockets, 127.0.0.1 loopback vs 0.0.0.0 wildcard binding security, socket auditing with ss and lsof, Netfilter kernel hooks, nftables host firewall rulesets, and network namespaces.
Master Linux authentication architecture: Pluggable Authentication Modules (PAM) stacks and control flags, SSH public key cryptography and key exchange, sshd_config hardening, sudoers privilege delegation, secret hygiene, and brute-force defenses (pam_faillock, fail2ban).
Master host observability and forensic auditing: plain-text syslog vs structured binary journald, advanced journalctl query syntax, the in-kernel Linux Audit Framework (auditd), authoring auditctl rules, ausearch/aureport incident response, and log anti-tampering defenses.
Explore enterprise hardening methodologies: CIS Benchmarks, STIG baselines, sysctl kernel tunables, filesystem mount flags (noexec, nosuid, nodev), attack surface minimization, blacklisting unneeded kernel modules, time synchronization, and automated audits with Lynis.
Break the root monolith with POSIX Capabilities. Understand capability sets (Permitted, Effective, Inheritable, Bounding, Ambient), manage capabilities with capsh/getcap/setcap, analyze high-risk capabilities, container isolation primitives (namespaces, cgroups), and seccomp syscall filtering.
Deconstruct software packaging and supply chain integrity: APT vs RPM/DNF architectures, cryptographic GPG signatures, repository trust hierarchies, risks of third-party PPAs and curl-pipe-bash installers, Software Bill of Materials (SBOM), and automated patching.
Execute 100% locally runnable, safe simulations and artifact-based triage labs: host baseline reconnaissance, user account and shadow audits, dangerous SUID triage, live process and socket hunting, systemd and SSH hardening, and forensic auth log investigation.