hardMultiple Choice
ISC2 CC Practice Question: In a defense-in-depth strategy, which access…
In a defense-in-depth strategy, which access control mechanism provides the most granular control over user permissions?
⚠ Common exam trap
ISC2 often tests the distinction between network-level controls (like firewall rules and segmentation) and system-level controls (like file ACLs), leading candidates to mistakenly choose a network mechanism when the question asks for the most granular control over user permissions on a resource.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Access control lists (ACLs) on files
Access control lists (ACLs) on files provide the most granular control because they allow permissions to be set at the individual file or object level, specifying exactly which users or groups can read, write, execute, or modify that specific resource. This is in contrast to broader mechanisms like network segmentation or firewall rules, which operate at the network or subnet level and cannot distinguish between individual files within a system. ACLs are a fundamental component of discretionary access control (DAC) and are implemented in file systems such as NTFS, ext4, and ZFS.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Network segmentation
Why it's wrong here
Network segmentation divides infrastructure into zones to limit lateral movement; it governs traffic paths, not individual user permissions. It is tempting because segmentation is central to defence in depth, so it would be correct if the question asked how to contain a breach rather than which mechanism gives the finest-grained user authorisation.
- ✓
Access control lists (ACLs) on files
Why this is correct
ACLs specify permissions per individual user or group against each file, giving far finer granularity than role-based or mandatory models. This directly satisfies the stem's requirement for the most granular control over user permissions within defence in depth.
- ✗
Physical security controls
Why it's wrong here
Physical controls restrict access to facilities and hardware, not individual user permissions within systems. It is tempting because defence in depth genuinely includes physical layers, so it would be correct if the question asked which control prevents unauthorised onsite access rather than which grants granular per-user rights.
- ✗
Firewall rules
Why it's wrong here
Firewall rules filter traffic by address, port and protocol at network boundaries; they cannot express per-user permissions on resources. It is tempting because firewalls are a foundational defence-in-depth layer, so they would be correct if the question asked how to restrict inbound network traffic rather than how to control individual user rights.
Visual reference
Quick reference
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
Go deeper
Related to this question
Learn chapter
Network Security Components and Controls
Key term
Least privilege
Least privilege is a security principle that means giving users, systems, or programs only the minimum permissions they need to do their job and nothing more.
Key term
Firewall
A firewall is a network security system that monitors and controls incoming and outgoing traffic based on predetermined security rules to protect trusted internal networks from untrusted external networks.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CC practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CC exam.