Skill · Linux · Harden a Linux server against a baseline
Confine a service: mandatory access control (SELinux or AppArmor), then systemd sandboxing
Confine a service with SELinux or AppArmor, troubleshoot a denial without disabling everything, then restrict what it can do with systemd sandboxing.
Start lesson 1The Linux domain
- 2 lessons
- ~2 h 30 of reading
- 3 quizzes
- 2 proof labs
The path
Where it comes from, where it leads
What you need to know first, where you stand on this skill, and what it opens next. Your status is computed in your browser, from what you have read and passed.
Before · 2 prerequisites
Recommended before · 1
This skill, for you
Confine a service: mandatory access control (SELinux or AppArmor), then systemd sandboxing
Computing
It unlocks · nothing yet
No other skill requires it: it is an end-of-path skill.
The path through the foundations From the most upstream foundation to this skill: what is in place, what remains to read.
Lessons
How to learn it
This skill is learned with the tool of your choice; your preferences decide the path followed in your journey. Each path lists its lessons in program order.
With SELinux
2 lessons · ~2 h 30 default
With AppArmor
2 lessons · ~1 h 15
Beyond the lessons
Assess, practise, pass the proof
Reading a lesson confirms nothing. A skill is confirmed by a passed quiz, practised in a guided lab, and put to the test by a challenge or a mission; an imported lab result is not verified by the site.
Assess yourself
3 quizzes
At the end of the lessons: passed at 70%, they confirm the skill.
Practice
4 guided labs
Proof
2 practical proofs
A practical proof is a challenge, a capstone or a declared lab.
Placement test
Preparing the questions…
Your answers in detail
For each question asked: your answer, the correct answer, its explanation and the page to reread.
Around it
Who requires it, who teaches it
Required by
- Linux Administrator
- LFCS
- RHCSA (EX200, RHEL 10)
In red: the certification it prepares for.
Taught by
Tool of your choice: SELinux or AppArmor.
Same block · Harden a Linux server against a baseline
- Measure a server's gap to a hardening baseline and prioritize the measures (ANSSI-BP-028, CIS)
- Harden a server's access and privileges: SSH, PAM, sudo, permissions and scheduling
- Harden boot, mounts and the local session: GRUB, nodev, nosuid, noexec, banners, dconf
- Harden the running kernel: persistent sysctl parameters and blocked modules
- Trace who did what on a Linux server with auditd: persistent rules, ausearch and aureport
- Rebuild a KSPP-hardened kernel and prove its options at boot
- Harden a NixOS server declaratively: versioned measures, test before switching, runtime checks and rollback to a healthy generation