Skip to content

Linux hardening

Intermediate5 sections · 16 lessons · ~5h total · 50-question self-test

01

Access hardening

5 lessonsTest yourself

01SSH hardeningKeys only, no root, minimal exposure.14 min 02Keys, MFA & bastionsStrong auth and a single front door.12 min 03Accounts & PAM policyPassword rules, lockout, and login limits.12 min 04Hardening sudoNarrow rules, logging, and the escape hatches.10 min 05Scheduled-task hardeningcron & timer privilege boundaries and PATH hijack.12 min

02

Network hardening

3 lessonsTest yourself

01A default-deny firewall (nftables)A host firewall you can actually read.14 min 02Network kernel hardening (sysctl)No forwarding, no redirects, sane defaults.12 min 03Minimize services & exposureEvery listener you remove is risk removed.10 min

03

Kernel & filesystem

3 lessonsTest yourself

01Kernel & memory hardening (sysctl)ptrace, dmesg, kptr, and friends.12 min 02Kernel module controlBlacklist what you never load.10 min 03Mount options & filesystemnoexec, nosuid, nodev where they belong.12 min

04

Mandatory access control

2 lessonsTest yourself

01SELinux in enforcing, calmlyRead denials, write targeted modules, never disable.16 min 02AppArmor profilesPath-based confinement, complain to enforce.12 min

05

Audit & compliance

3 lessonsTest yourself

01auditd rules that matterIdentity files, privileged execs, module loads.14 min 02File integrity monitoringAIDE: know when the system changes.10 min 03CIS benchmarks with OpenSCAPScan, remediate, and track drift.12 min

Final exam

Test yourself on everything

50 questions drawn from all 5 sections — every answer explained as you pick.

Start final exam