hardMultiple Choice
SSCP Practice Question: Uses mandatory access control (MAC) with the…
An organization uses mandatory access control (MAC) with the Bell-LaPadula model. A subject has a clearance of 'Secret' and an object has a classification of 'Top Secret'. What is the result if the subject attempts to read the object?
⚠ Common exam trap
Watch out — candidates often confuse the Bell-LaPadula model with the Biba model (which focuses on integrity) or misapply the *-property to read operations, leading them to incorrectly select 'Read allowed' or 'Write allowed' when the actual rule is 'no read up'.
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
✓
Read denied
In the Bell-LaPadula model, the Simple Security Property (no read up) prohibits a subject from reading an object with a higher classification. Since the subject has a clearance of 'Secret' and the object is classified as 'Top Secret', the read attempt is denied. This enforces mandatory access control (MAC) by preventing information flow from higher to lower security levels.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Write denied
Why it's wrong here
The question asks about a read attempt, and Bell-LaPadula's simple security property already denies reads above clearance. Write denial concerns the star property, which restricts writing downward; it does not answer what happens when a Secret subject reads a Top Secret object.
- ✗
Write allowed
Why it's wrong here
Bell-LaPadula's simple security property forbids reading above clearance, so a Secret subject reading a Top Secret object is denied, not permitted to write. Write permission is irrelevant to a read attempt; the no-write-down property governs writing, not reading.
- ✓
Read denied
Why this is correct
Under Bell-LaPadula's no-read-up rule, a Secret-cleared subject cannot read a Top Secret object, so access is denied. This satisfies the mandatory access control constraint: clearance must dominate the object's classification. The simple security property blocks reads to higher classifications regardless of need, preventing unauthorised disclosure.
- ✗
Read allowed
Why it's wrong here
Bell-LaPadula's simple security property states no read up: a Secret-cleared subject cannot read a Top Secret object, so the attempt is denied. Read-up is permitted only under models such as Biba, which prioritise integrity rather than confidentiality.
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
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SSCP 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 SSCP exam.