Linux Baseline
Know the Linux hardening checklist — read and plan on $LAB_HOST only.
Visual · linux_baseline
Linux baseline literacy. $LAB_HOST only. Original Cyberlium.
uname and ss are not invitations to SSH into strangers.
Linux baselines cover kernel support, unnecessary packages, listening services, file permissions, and sudo policy. Defenders compare live state to CIS or distro guidance on servers they administer. Cyberlium teaches checklist literacy on $LAB_HOST — your lab VM or personal Linux box. You will NOT harden a university server, scan roommate Raspberry Pis, or change sshd on café kiosks. Next: Updates and SSH.
1. Baseline categories on Linux
Package inventory: what is installed? Listening ports: ss -tlnp or equivalent. Users and sudo: who can become root? Kernel: is the distro still supported?
On $LAB_HOST, read before you change — document like a blue-team host assessment.
Command guide
Try these commands — Baseline categories on Linux
═══ TOOLS & WEBSITES ═══ Browse / read these (authorized learning only — stay in YOUR lab / program scope)
CIS Linux benchmarks — https://www.cisecurity.org/cis-benchmarks Linux hardening — https://www.cyber.gov.au/resources-business-and-government/maintaining-devices-and-systems/system-hardening-and-administration/system-hardening/linux-hardening
═══ INSTALL ═══
Linux (Debian/Ubuntu): Built-in (iproute2)
macOS: Use: netstat
Windows: Use: netstat
═══ LINUX / macOS ═══
Command — copy this
ss -tulpn 2>/dev/null | head -15 dpkg -l 2>/dev/null | wc -l || rpm -qa 2>/dev/null | wc -l || echo 'Package count baseline on YOUR host'
Primary tools to practice this lesson: ss, dpkg. Reference sites: CIS Linux benchmarks (https://www.cisecurity.org/cis-benchmarks); Linux hardening (https://www.cyber.gov.au/resources-business-and-government/maintaining-devices-and-systems/system-hardening-and-administration/system-hardening/linux-hardening). Run every command in the box — install first, then the usage lines — only on YOUR lab / program scope.
2. Minimal install mindset
Fewer packages mean fewer CVEs. Defenders remove unused services; attackers love forgotten daemons. Lab literacy names the habit without touching stranger servers.
Copy-pasting hardening one-liners from blogs onto production you do not own is misuse.
3. Lab boundary
Verify hostname matches $LAB_HOST. Snapshot or backup before optional changes.
Ship: baseline category table for $LAB_HOST. Next: Updates and SSH.
4. What you ship: Linux baseline note for $LAB_HOST
Distro, kernel, listening ports summary, sudo users. $LAB_HOST only. chmod 600.
5. What you record before the next lesson
Date. $LAB_HOST uname and ss summary. NEVER stranger servers. File t16-m03-l01-linux-baseline.txt chmod 600.
6. Wrong vs right: stranger hosts vs YOUR lab hosts
Worked failure — same MSF word, opposite target. Right never needs a café Wi-Fi or classmate laptop.
- Wrong: SSH to university server and run hardening script. Change permissions on roommate's home directory.
- Right: Inventory baseline on $LAB_HOST. Next: Updates and SSH.
Mission: Linux baseline inventory
1) Record distro and kernel on $LAB_HOST. 2) List listening TCP ports (read-only). 3) Note sudo-capable users. Never harden Linux hosts you do not own.
Stuck? Ask Cyberlium AI Mentor
ss -tlnp shows listeners — read it before disabling 'random' services.
APPLY: Linux baseline literacy on Cyberlium uses:
APPLY: True or False: Running hardening scripts on a university server without ticket is in scope.
APPLY: Minimal install mindset reduces:
Updates and SSH
Part of Defensive Security Basics with AI — Linux Hardening Literacy.
Firewall (ufw/nftables literacy)
Part of Defensive Security Basics with AI — Linux Hardening Literacy.
Linux Lab
Part of Defensive Security Basics with AI — Linux Hardening Literacy.