- A
chown root:root /etc/shadow
Ensures owner and group are root.
- B
chmod 444 /etc/shadow
Why wrong: 444 is world-readable, which is insecure.
- C
chmod 600 /etc/shadow
Sets permissions to rw-------.
- D
chmod 640 /etc/shadow
Why wrong: 640 allows group read access, which is too permissive.
- E
chown root:shadow /etc/shadow
Why wrong: Changing group to shadow would allow group read if permissions allow.
Question 19 of 1,000
XK0-005 Security Practice Question
This XK0-005 practice question tests your understanding of security. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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.
A security administrator is reviewing file permissions on a Linux system. They want to ensure that the /etc/shadow file is only readable by the root user. Which two commands can be used to set the correct permissions?
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
✓
chown root:root /etc/shadow
Option A is correct because the chown root:root /etc/shadow command changes both the owner and group of the /etc/shadow file to root. This ensures that only the root user has ownership, which is a prerequisite for setting restrictive permissions. However, the question asks for commands to set the correct permissions, and while ownership change is important, the primary requirement is that the file is only readable by root, which is achieved by setting permissions to 600 (owner read/write, no access for group or others). Thus, chmod 600 /etc/shadow (Option C) is also correct, making A and C the two commands that together ensure the file is only readable by root.
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.
- ✓
chown root:root /etc/shadow
Why this is correct
Ensures owner and group are root.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
chmod 444 /etc/shadow
Why it's wrong here
444 is world-readable, which is insecure.
- ✓
chmod 600 /etc/shadow
Why this is correct
Sets permissions to rw-------.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
chmod 640 /etc/shadow
Why it's wrong here
640 allows group read access, which is too permissive.
- ✗
chown root:shadow /etc/shadow
Why it's wrong here
Changing group to shadow would allow group read if permissions allow.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse the purpose of chown and chmod, thinking that changing ownership alone (Option A) is sufficient to restrict access, when in fact the permission bits (like 600) must also be set to deny group and others access, or they mistakenly choose chmod 640 (Option D) assuming the shadow group is acceptable, but the question explicitly requires only root to have read access.
Detailed technical explanation
How to think about this question
The /etc/shadow file stores hashed user passwords and must be protected from unauthorized access to prevent offline password cracking. The standard permission is 600 (or 640 in some configurations where the shadow group is used for specific tools), but the strictest security practice for a system where only root should read it is 600. The chown command changes file ownership, which interacts with permission bits: the owner always has access as defined by the owner bits, and the group has access as defined by the group bits. Setting the group to root (root:root) ensures no other group has inherent read access, complementing the 600 permission mask.
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 practitioner preparing for the XK0-005 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
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.
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FAQ
Questions learners often ask
What does this XK0-005 question test?
Security — This question tests Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: chown root:root /etc/shadow — Option A is correct because the chown root:root /etc/shadow command changes both the owner and group of the /etc/shadow file to root. This ensures that only the root user has ownership, which is a prerequisite for setting restrictive permissions. However, the question asks for commands to set the correct permissions, and while ownership change is important, the primary requirement is that the file is only readable by root, which is achieved by setting permissions to 600 (owner read/write, no access for group or others). Thus, chmod 600 /etc/shadow (Option C) is also correct, making A and C the two commands that together ensure the file is only readable by root.
What should I do if I get this XK0-005 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
This XK0-005 practice question is part of Courseiva's free CompTIA 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 XK0-005 exam.
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