ISC2 CC Access Controls Concepts Practice Question
Which principle ensures that a user is granted only the permissions necessary to perform their job functions, thereby reducing the potential impact of a compromised account?
⚠ Common exam trap
The trap is conflating least privilege with need-to-know — both restrict access, but least privilege governs permissions/rights while need-to-know governs data classification access.
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
✓
Least privilege
Least privilege is the principle that users, processes, and systems should be granted only the minimum access rights required to perform their legitimate tasks, and no more. This limits the blast radius if an account is compromised, because the attacker inherits only the narrow permissions of that account. It is a foundational concept in access control and is explicitly required by standards like NIST SP 800-53 (AC-6).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Least privilege
Why this is correct
Least privilege restricts user access rights to the minimum set of permissions required to complete assigned job functions, directly satisfying the stem’s requirement to reduce the impact of a compromised account. By enforcing granular permission boundaries—such as read-only access to specific Microsoft Entra ID resources rather than full administrative roles—this principle limits lateral movement and data exposure if credentials are stolen.
- ✗
Need-to-know
Why it's wrong here
Need-to-know restricts access to specific data based on relevance to a task, not to the minimum permissions for a job role. It is tempting because both limit exposure, but least privilege governs permission scope, which is what the stem describes.
- ✗
Separation of duties
Why it's wrong here
Separation of duties splits critical tasks across multiple people to prevent fraud, rather than limiting each user's permission set. It is tempting because both reduce insider risk, but the stem describes least privilege, which caps permissions to job function.
- ✗
Defense in depth
Why it's wrong here
Defense in depth layers multiple independent controls so no single failure exposes the estate; it does not limit individual permission scope. It is tempting because it also reduces compromise impact, but the stem describes least privilege, which caps permissions to job function.
Quick reference
AAA Protocol Comparison
| Protocol | Port(s) | Encryption | Transport | Primary Use |
|---|---|---|---|---|
| RADIUS | 1812 / 1813 | Password only | UDP | Network access control |
| TACACS+ | 49 | Full packet | TCP | Device administration |
| Diameter | 3868 | Full session | TCP / SCTP | Carrier / mobile networks |
| 802.1X | — | EAP-based | Layer 2 | Port-based access control |
TACACS+ encrypts the entire packet; RADIUS only encrypts the password field — a key exam distinction.
Go deeper
Related to this question
Learn chapter
Access Control Fundamentals
Key term
Access control
Access control is the security practice of determining who or what is allowed to view, use, or enter a resource, and under what conditions.
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.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official ISC2 exam blueprint
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