Courseiva
← LPIC-1
Full test
Question 331 of 532
Devices, Filesystems and FHS →hardMultiple ChoiceObjective-mapped

LPIC-1 Devices, Filesystems and FHS Practice Question

This LPIC-1 practice question tests your understanding of devices, filesystems and fhs. 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.

Exhibit

$ ls -la /usr/local/bin/myapp
-rwsr-xr-x 1 root root 12345 Jan 1 00:00 /usr/local/bin/myapp
$ sudo -u user1 /usr/local/bin/myapp
Error: Permission denied
$ id user1
uid=1001(user1) gid=1001(user1) groups=1001(user1)
$ getfacl /usr/local/bin/myapp
# file: usr/local/bin/myapp
# owner: root
# group: root
user::rwx
group::r-x
other::r-x

Refer to the exhibit. A user 'user1' tries to run the setuid binary 'myapp' but gets permission denied. What is the most likely reason?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "most likely"

    Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

Exhibit

$ ls -la /usr/local/bin/myapp
-rwsr-xr-x 1 root root 12345 Jan 1 00:00 /usr/local/bin/myapp
$ sudo -u user1 /usr/local/bin/myapp
Error: Permission denied
$ id user1
uid=1001(user1) gid=1001(user1) groups=1001(user1)
$ getfacl /usr/local/bin/myapp
# file: usr/local/bin/myapp
# owner: root
# group: root
user::rwx
group::r-x
other::r-x

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

✓

The binary has the setuid bit set, but the filesystem is mounted with 'nosuid'

Option C is correct because when a filesystem is mounted with the 'nosuid' option, the kernel ignores setuid and setgid bits on executables within that filesystem. Even if 'myapp' has the setuid bit set, the nosuid mount flag prevents the effective UID from changing to the file owner, so 'user1' still runs the binary with their own privileges and may receive 'Permission denied' if the binary requires root-level access.

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.

  • ✗

    The binary is missing the setgid bit

    Why it's wrong here

    Missing setgid does not cause permission denied; it just doesn't set group.

  • ✗

    The binary is not executable by others

    Why it's wrong here

    The permissions show r-x for others, so user1 has execute permission.

  • ✓

    The binary has the setuid bit set, but the filesystem is mounted with 'nosuid'

    Why this is correct

    If the filesystem is mounted with 'nosuid', setuid bits are ignored, so the program runs with the user's privileges, and the error might be due to insufficient permissions for the operation.

    Clue confirmation

    The clue word "most likely" in the question point toward this answer.

    Related concept

    Read the scenario before looking for a memorised answer.

  • ✗

    The user does not belong to the root group

    Why it's wrong here

    The setuid bit elevates to owner (root), so group membership is not required for execution.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates often focus on file permissions (e.g., missing execute bit or group membership) and overlook the filesystem mount option 'nosuid', which silently disables setuid/setgid behavior regardless of the binary's permission bits.

Trap categories for this question

  • Command / output trap

    The permissions show r-x for others, so user1 has execute permission.

Detailed technical explanation

How to think about this question

The 'nosuid' mount option is commonly used on removable media (e.g., USB drives) and network filesystems (e.g., NFS with the 'nosuid' default) to prevent privilege escalation. Under the hood, the kernel's do_execve() function checks the mount flags via the VFS layer; if MS_NOSUID is set, it clears the setuid and setgid bits from the inode's mode before applying the effective UID change. This is a security mechanism to prevent users from bringing their own setuid binaries from untrusted filesystems.

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 junior network technician can log in to a core router but cannot reach the enable prompt or configuration mode. The AAA server is authenticating the login — but the authorisation policy only grants privilege level 1, not 15. Authentication (who you are) is working; authorisation (what you can do) is not.

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.

Related practice questions

Related LPIC-1 practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

GNU and Unix Commands practice questions

Practise LPIC-1 questions linked to GNU and Unix Commands.

Devices, Filesystems and FHS practice questions

Practise LPIC-1 questions linked to Devices, Filesystems and FHS.

Linux Installation and Package Management practice questions

Practise LPIC-1 questions linked to Linux Installation and Package Management.

Essential System Services and Networking practice questions

Practise LPIC-1 questions linked to Essential System Services and Networking.

Administrative Tasks practice questions

Practise LPIC-1 questions linked to Administrative Tasks.

Shells, Scripting and Data Management practice questions

Practise LPIC-1 questions linked to Shells, Scripting and Data Management.

System Architecture practice questions

Practise LPIC-1 questions linked to System Architecture.

LPIC-1 fundamentals practice questions

Practise LPIC-1 questions linked to LPIC-1 fundamentals.

LPIC-1 scenario practice questions

Practise LPIC-1 questions linked to LPIC-1 scenario.

LPIC-1 troubleshooting practice questions

Practise LPIC-1 questions linked to LPIC-1 troubleshooting.

Practice this exam

Start a free LPIC-1 practice session

Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.

10 questions20 questions30 questions50 questionsTimed 30
LPIC-1 practice-test guide →Study guide →Browse all practice tests

FAQ

Questions learners often ask

What does this LPIC-1 question test?

Devices, Filesystems and FHS — This question tests Devices, Filesystems and FHS — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The binary has the setuid bit set, but the filesystem is mounted with 'nosuid' — Option C is correct because when a filesystem is mounted with the 'nosuid' option, the kernel ignores setuid and setgid bits on executables within that filesystem. Even if 'myapp' has the setuid bit set, the nosuid mount flag prevents the effective UID from changing to the file owner, so 'user1' still runs the binary with their own privileges and may receive 'Permission denied' if the binary requires root-level access.

What should I do if I get this LPIC-1 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: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

About these practice questions

Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →

How Courseiva writes practice questions · Editorial policy

Keep practising

More LPIC-1 practice questions

Browse all LPIC-1 questions →

Last reviewed: Jul 4, 2026

Question Discussion

Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.

Loading comments…

Sign in to join the discussion.

This LPIC-1 practice question is part of Courseiva's free LPI 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 LPIC-1 exam.