hardMultiple ChoiceObjective-mapped
XK0-006 Practice Question: Ensure that /var/log/secure is only readable by…
An administrator needs to ensure that /var/log/secure is only readable by members of the 'adm' group and is not accessible by any other user. Additionally, new files created in /var/log should inherit the group ownership 'adm'. Which set of commands achieves this?
⚠ Common exam trap
CompTIA often tests the distinction between setting group ownership on a file versus a directory, and the requirement to use the setgid bit for inheritance, which candidates frequently overlook by only changing permissions on the file itself.
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
✓
chgrp adm /var/log; chmod g+s /var/log; setfacl -m g:adm:rx /var/log/secure
Ly sets the group ownership of /var/log to 'adm' with `chgrp adm /var/log`, enables the setgid bit on the directory with `chmod g+s /var/log` so new files inherit the 'adm' group, and uses `setfacl -m g:adm:rx /var/log/secure` to grant only the 'adm' group read and execute access to the secure log file, while removing permissions for others via the default ACL mask.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
setfacl -m u::rwx,g::rwx,o::--- /var/log/secure; chmod g+s /var/log
Why it's wrong here
ACL incorrectly gives group rwx instead of rx, and order of operations is fine but the ACL is too permissive.
- ✓
chgrp adm /var/log; chmod g+s /var/log; setfacl -m g:adm:rx /var/log/secure
Why this is correct
Sets group ownership, sgid on directory, and ACLs to make /var/log/secure readable by adm group only.
- ✗
chown :adm /var/log/secure; chmod 640 /var/log/secure
Why it's wrong here
While chmod 640 sets owner read/write and group read, it does not set sgid on /var/log, so new files will not inherit group.
- ✗
usermod -aG adm $(whoami); chmod 640 /var/log/secure
Why it's wrong here
This adds the user to adm group but does not set inheritance for new files.
Visual reference
Go deeper
Related to this question
Learn chapter
File Permissions and Ownership
Key term
User
A user is any person, system, or device that interacts with an IT service, resource, or identity system, typically authenticated through credentials and authorized to perform specific actions.
Key term
chmod
chmod is a command in Linux and Unix-like operating systems used to change the permissions (read, write, execute) of a file or directory.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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