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multiple_choice hard Understand setuid 2 points

Question 4. CSCD240-E1-C

A -rwsr-xr-x file owned by root. Execution causes what?

Work the drill

Answer on paper or in a terminal before revealing the ideal answer.

Ideal answer
B: Process runs with effective UID of root

Misconception bank

Each row below is a plausible wrong answer, the thinking that produces it, and the remedy that corrects the misconception. These are the foundation of the multiple-choice framing and the targeted feedback a student receives after answering.

A: Runs as invoking user
Misconception. That is the default; the s changes it.
Remedy. Teach the mechanic.
C: Cannot run
Misconception. s in owner x position still allows execution.
Remedy. Capital S means x missing too; lowercase s = both x AND setuid.
D: Prompts for password
Misconception. Passwords are not a setuid feature; that is sudo.
Remedy. setuid is silent elevation.

Authority mappings

Hover any chip for the mapping justification; click to open the authority record.

DCWF tasks: T0250
KU outcomes: CO-M10-O1CO-M6-O1
KU topics: CD-OSC-T7
NCAE errors: SMB Login / failure: SMB operation failed: [Errno.SMB Login / failure: SMB operation failed: [Errno.SMB Login / failure: SMB connection failed: proto.

Course-artifact links

Lectures

  • CSCD240-S26-L05. Permissions part 1: ls -l anatomy, rwx, file types

CTF challenges

  • 99 BONUS: Lecture Recall: What Does the S Stand For?