The answer is to set readOnlyRootFilesystem to true. This security enhancement mounts the container’s root filesystem as read-only, preventing attackers from modifying binaries, libraries, or configuration files at runtime, which directly limits the blast radius of a compromise. On the Certified Cloud Security Professional CCSP exam, this concept tests your understanding of container hardening and the CIS Benchmark for Kubernetes, often appearing in scenario-based questions where a pod lacks immutable filesystem controls. A common trap is confusing ephemeral storage with root filesystem permissions—remember that readOnlyRootFilesystem applies to the container’s root mount, not volumes. For a quick memory tip, think “read-only root, read-proof compromise.”
CCSP Cloud Application Security Practice Question
This CCSP practice question tests your understanding of cloud application security. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
Refer to the exhibit.
```
apiVersion: v1
kind: Pod
metadata:
name: web-app
spec:
containers:
- name: web
image: nginx:latest
securityContext:
runAsUser: 1000
runAsGroup: 3000
allowPrivilegeEscalation: false
ports:
- containerPort: 80
```
Refer to the exhibit. A Kubernetes pod is configured as shown. Which security enhancement should be added to follow cloud security best practices?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Set readOnlyRootFilesystem to true
Setting `readOnlyRootFilesystem` to true ensures the container's root filesystem is mounted as read-only, preventing attackers from modifying binaries, libraries, or configuration files at runtime. This is a key container hardening practice that limits the blast radius of a compromise, aligning with the CIS Benchmark for Kubernetes and cloud security best practices.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Set allowPrivilegeEscalation to true
Why it's wrong here
Setting to true would increase risk.
✗
Use a more restrictive runAsUser value like 2000
Why it's wrong here
Current value is already non-root; changing UID does not add security.
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use a trusted image from a private registry
Why it's wrong here
Image source is important but not shown as a vulnerability.
Common exam traps
Common exam trap: answer the scenario, not the keyword
ISC2 often tests the distinction between runtime hardening (like read-only filesystem) and identity/access controls (like runAsUser or image trust), expecting candidates to recognize that a non-root user alone does not prevent file tampering.
Trap categories for this question
Command / output trap
Image source is important but not shown as a vulnerability.
Detailed technical explanation
How to think about this question
Under the hood, `readOnlyRootFilesystem` leverages Linux kernel mount namespaces to remount the root filesystem as read-only; any write attempt returns an error unless a writable volume (e.g., emptyDir) is explicitly mounted. In a real-world scenario, if an attacker exploits a web application vulnerability to write a webshell, a read-only root filesystem prevents persistence, forcing the attacker to rely on ephemeral volumes that are wiped on pod restart. This setting is also a requirement for Pod Security Standards (Restricted profile) and is enforced by admission controllers like OPA/Gatekeeper.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A developer is choosing between AES-256 (symmetric) and RSA-2048 (asymmetric) for encrypting a large file that will be sent to a partner. Symmetric encryption is fast but requires key exchange; asymmetric is slower but solves the key distribution problem. A hybrid approach — encrypt the file with AES, encrypt the AES key with RSA — is standard. Questions like this test whether you understand when each approach applies.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Cloud Application Security — This question tests Cloud Application Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Set readOnlyRootFilesystem to true — Setting `readOnlyRootFilesystem` to true ensures the container's root filesystem is mounted as read-only, preventing attackers from modifying binaries, libraries, or configuration files at runtime. This is a key container hardening practice that limits the blast radius of a compromise, aligning with the CIS Benchmark for Kubernetes and cloud security best practices.
What should I do if I get this CCSP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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