System Security & User Permissions Flashcards
7 cards from real 010-160 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 System Security & User Permissions flashcards as text
Which file defines which users and groups can use sudo?
Answer: /etc/sudoers
/etc/sudoers (edited safely with visudo) controls sudo access policies.
How would you add an existing user 'alice' to the 'wheel' group without removing her from other groups?
Answer: usermod -aG wheel alice
`usermod -aG wheel alice` appends (-a) alice to the supplementary group (-G) wheel.
What does 'umask 027' mean for newly created files?
Answer: Files get permissions 640
Default file permissions (666) minus umask (027) = 640, giving rw-r----- for new files.
Which command locks a user account so they cannot log in with a password?
Answer: usermod -L username
`usermod -L username` locks the account by prepending a '!' to the password hash in /etc/shadow.
In the output of `ls -l`, what does the first character 'd' indicate?
Answer: The item is a directory
A 'd' as the first character of the permission string indicates the item is a directory.
What is the numeric (octal) representation of permissions rwxr-xr-x?
Answer: 755
rwx=7, r-x=5, r-x=5 → 755.
Which command shows failed login attempts on a Linux system?
Answer: lastb
`lastb` reads /var/log/btmp and displays a list of failed login attempts.