LFCS Question #265: Real Exam Question with Answer & Explanation

Question

Which of the following should the permission settings be for /etc/passwd and /etc/shadow?

Options

• A/etc/passwd: -rw-r--r-- /etc/shadow: -r--------
• B/etc/passwd: -r-------- /etc/shadow: -rw-r--r--
• C/etc/passwd: -rw-r--r-- /etc/shadow: -rw-r--r--
• D/etc/passwd: -r-------- /etc/shadow: -r--------}

Explanation

File permissions for /etc/passwd allow all users to read basic account information, while /etc/shadow is restricted to root-only read access to protect password hashes.

Common mistakes.

• B. This option incorrectly restricts /etc/passwd to root-only read, which breaks common system functionality, and grants too much read/write access to /etc/shadow.
• C. This option grants read and write access to /etc/shadow to all users, which is a severe security vulnerability.
• D. This option restricts /etc/passwd to root-only read, which would prevent many services and users from functioning correctly, and provides correct but incomplete permissions for shadow.

Concept tested. /etc/passwd and /etc/shadow permissions

Reference. https://man7.org/linux/man-pages/man5/passwd.5.html

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