ISC2-CC - Network Security - Section 4.3

Understand network security infrastructure, including firewalls, IDS/IPS, segmentation, VLANs, VPNs, and cloud and zero-trust concepts.

Distinguish the devices and designs that secure a network - firewalls that filter traffic, intrusion detection and prevention systems (IDS/IPS), network segmentation, VLANs, and VPNs that encrypt traffic over untrusted links. Recognise cloud network models and the zero-trust principle of never trusting, always verifying, regardless of network location.

FirewallIDS/IPSNetwork segmentationVPNZero trust

Practice question for this objective

Free sampleNetwork Securityhard

A cloud architect is explaining the guiding principle of a zero-trust architecture to stakeholders who are used to a traditional perimeter model. Which statement best expresses the central premise of zero trust?

  • ANo user or device is trusted by default regardless of location, and each access request is authenticated and authorised on its own merits. Correct
  • BDevices located inside the corporate network are inherently trusted, so internal traffic can move freely once a user is past the perimeter firewall.
  • CTrust is granted once at initial login and persists for the whole session, avoiding repeated checks that would slow users down.
  • DTrust is established purely by the strength of the network encryption, so a well-encrypted link needs no further identity checks.
Zero trust grants no implicit trust based on network location and verifies every access request explicitly under least privilege. Zero trust replaces perimeter-based implicit trust with continuous verification: each request is authenticated and authorised on its own merits, so being inside the network grants no automatic access.

Why A is correct: Correct. Zero trust assumes no implicit trust based on network position and verifies every access request explicitly, applying least privilege per request.

Why B is wrong: Tempting because it reflects the older perimeter model, but zero trust explicitly rejects the idea that internal location confers trust.

Why C is wrong: Zero trust favours continuous, per-request evaluation rather than a single durable grant; a one-time check contradicts its core stance.

Why D is wrong: Encryption protects data in transit but does not establish identity or authorisation; zero trust still requires verifying who and what is requesting access.

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