Security › Module 2 › Lesson 2
People Process Tech
Perimeter vs zero trust literacy names castle-and-moat assumptions, identity-centric verification, and micro-segmentation — compare models for YOUR $ARCH_LAB fictional org before design decisions.
Visual · t41_perimeter_zero_trust
Perimeter vs zero trust literacy. $ARCH_LAB only. Original Cyberlium.
Opening
Perimeter alone fails inside the wall — literacy teaches when zero trust principles complement segmentation on documented fictional scenarios at $ARCH_LAB.
Traditional perimeter models trust inside the network boundary — VPN lands users in a soft interior. Zero trust assumes breach — verify every user, device, and workload explicitly regardless of network location. Both require documented trust assumptions on YOUR lab template; neither authorizes attack paths against real targets. Cyberlium writes model comparison row on YOUR $ARCH_LAB — fictional scenario, perimeter assumption, zero trust countermeasure, hybrid note for LAB-ARCH-001. Next: Compensating Controls.
1. Perimeter vs zero trust (named)
Perimeter: strong edge controls, implicit internal trust — common in legacy fictional org labs. Zero trust: identity verification, least privilege, micro-segmentation, continuous validation — when lateral movement risk dominates. Hybrid: segmented perimeter plus identity checks on sensitive LAB-ARCH-001 workloads.
On $ARCH_LAB, write comparison row — scenario, perimeter weakness, zero trust principle applied, design note.
Command guide
Try these commands — Perimeter vs zero trust (named)
═══ TOOLS & WEBSITES ═══ Browse / read these (authorized learning only — stay in YOUR lab / program scope)
OWASP ASVS — https://owasp.org/www-project-application-security-verification-standard/ NIST 800-53 — https://csrc.nist.gov/publications/detail/sp/800-53/rev-5/final Microsoft SDL — https://www.microsoft.com/en-us/securityengineering/sdl/
═══ INSTALL ═══
Linux (Debian/Ubuntu):
Command — copy this
sudo apt install python3
macOS:
Command — copy this
brew install python3
Windows: Download https://python.org/downloads/
═══ LINUX / macOS ═══
Command — copy this
export ARCH_LAB=${ARCH_LAB:-$HOME/cyberlium-lab/t41-arch}
cat > "$ARCH_LAB/notes/cia-did-named.txt" <<'EOF'
CIA + Defense-in-Depth — NAMED LITERACY:
Confidentiality: limit disclosure (encryption, access control, segmentation)
Integrity: prevent unauthorized change (signing, validation, audit logs)
Availability: maintain service (redundancy, DDoS mitigation literacy, backups)
Defense-in-Depth: layered controls — no single point of failure
Layers (example): perimeter, network, host, application, data, governance
Lab: defense-in-depth-layers.md in Module 3 — fictional LAB-ARCH-001 only
EOFCommand — copy this
grep -E 'Confidentiality|Defense-in-Depth|Layers' "$ARCH_LAB/notes/cia-did-named.txt"
python3 -c "print('CIA + layered defense: literacy for YOUR fictional SaaS architecture')"Primary tools to practice this lesson: grep, python3. Reference sites: OWASP ASVS (https://owasp.org/www-project-application-security-verification-standard/); NIST 800-53 (https://csrc.nist.gov/publications/detail/sp/800-53/rev-5/final); Microsoft SDL (https://www.microsoft.com/en-us/securityengineering/sdl/). Run every command in the box — install first, then the usage lines — only on YOUR lab / program scope.
2. Why model choice affects control placement
Mislabeling internal VLAN as trusted skips MFA on admin consoles. Over-applying zero trust to every lab printer wastes complexity. Documented model rationale survives architecture board questions on fictional templates.
Students pick lab model on notes with rationale — production selection follows enterprise architecture standards.
3. Lab boundary
Forbidden: using comparison notes to blueprint attack paths against real perimeter devices. Allowed: perimeter vs zero trust card — comparison with $ARCH_LAB fictional org example.
Ship: model comparison row for YOUR lab scenario. Next: Compensating Controls.
4. What you ship: perimeter vs zero trust row for $ARCH_LAB
Scenario, perimeter assumption, zero trust principle, hybrid note. $ARCH_LAB named. chmod 600.
5. What you record before the next lesson
Date. Model comparison row. $ARCH_LAB named. File t41-m02-l02-perimeter-zero-trust.txt chmod 600.
6. Wrong vs right: offensive playbooks vs YOUR threat models
Worked failure — same MSF word, opposite target. Right never needs a café Wi-Fi or classmate laptop.
Wrong
Declare entire LAB-ARCH-001 trusted because 'we have a firewall.' Use zero trust label with no identity verification.
Right
Write perimeter vs zero trust comparison for YOUR $ARCH_LAB. Next: Compensating Controls.
Mission: compare models on YOUR lab scenario
1) Pick one fictional LAB-ARCH-001 scenario. 2) Name perimeter assumption and weakness. 3) Name zero trust countermeasure. 4) chmod 600.
Stuck? Ask Cyberlium AI Mentor
Zero trust is verify explicitly — not 'buy a vendor product and rename the network.'
Knowledge Check
APPLY: Zero trust primarily assumes:
Multiple choice
Knowledge Check
APPLY: True or False: Perimeter models often trust resources inside the network boundary.
True or False
Knowledge Check
APPLY: Perimeter vs zero trust literacy on Cyberlium uses:
Multiple choice