mediumMultiple Choice
SSCP Practice Question: A military system uses mandatory access control…
A military system uses mandatory access control with classifications Unclassified, Confidential, Secret, and Top Secret. A user with Secret clearance attempts to read a file labeled Top Secret. What will occur?
⚠ Common exam trap
Test-takers frequently confuse mandatory access control with discretionary access control, assuming that ownership or need-to-know can override classification labels, but in MAC, clearance level is the primary and non-negotiable gate for read 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
✓
Access is denied because the subject's clearance is lower than the object's classification
In a mandatory access control (MAC) system, access decisions are based on comparing the subject's clearance level with the object's classification label. Since the user has a Secret clearance and the file is classified Top Secret, the subject's clearance is lower than the object's classification, so read access is denied per the Bell-LaPadula model's Simple Security Property (no read up).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Access is denied because the subject's clearance is lower than the object's classification
Why this is correct
Under mandatory access control, the no-read-up rule enforces that a subject's clearance must dominate the object's classification. Here the Secret clearance is lower than the Top Secret label, so the read is refused regardless of need-to-know or any discretionary permission. This satisfies the stem's constraint that classification levels govern access.
- ✗
Access is granted because the user has write permission
Why it's wrong here
Write permission is irrelevant to a read attempt and, under mandatory access control, a Secret subject cannot read Top Secret data regardless of permissions. It is tempting because permissions matter in discretionary models, but Bell-LaPadula's no-read-up property blocks this access outright.
- ✗
Access is granted if the user is the owner of the file
Why it's wrong here
Ownership is a discretionary control that mandatory access control ignores; a Secret-cleared owner still cannot read a Top Secret file. It is tempting because owners normally control access to their files, but the classification label, not ownership, determines the outcome under Bell-LaPadula.
- ✗
Access is granted because the user has a need-to-know
Why it's wrong here
Need-to-know is a discretionary criterion layered on top of clearance; it cannot override the Bell-LaPadula no-read-up rule, so a Secret subject cannot read Top Secret data. It is tempting because need-to-know governs access in many systems, but mandatory labels take precedence here.
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 |
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Same concept, more angles
1 more way this is tested on SSCP
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company implements mandatory access control (MAC) on its classified document system. A user with a security clearance of Secret attempts to read a document labeled Top Secret. What happens?
medium- A.The user is prompted to request a temporary upgrade
- ✓ B.The access is denied by the system
- C.The document is downgraded to Secret for the user
- D.The user can read the document because they have a valid clearance
Why B: In a mandatory access control (MAC) system, access decisions are based on comparing the user's security clearance (Secret) with the document's classification label (Top Secret). Since the clearance level is lower than the document's classification, the system automatically denies the read operation. This is a fundamental property of MAC, where the system enforces the Bell-LaPadula model's simple security property (no read up).
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.