010-160 Security And File Permissions — 15 Questions

Question 1

You are managing a directory shared by a project team. You want all files created in this directory to automatically belong to the 'developers' group, regardless of the user's primary group. Which command achieves this?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

chmod g+s /data. Setting the setgid bit (chmod g+s) on a directory ensures that new files created within inherit the group ownership of the directory.

Answer

usermod -aG developers

Answer

chgrp developers /data

Answer

chmod 1777 /data

Question 2

You want to change the primary group of an existing user named 'bob' to 'staff'. Which command should you use?

Accepted Answer

usermod -g staff bob. The 'usermod -g' command is used to modify the primary group of an existing user account.

Answer

groupmod -n staff bob

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chgrp staff bob

Answer

usermod -G staff bob

Question 3

A system administrator needs to identify the numerical ID (UID) of the user 'jdoe'. Which file should be checked?

Accepted Answer

/etc/passwd. The /etc/passwd file contains user account information, including the username, UID, GID, home directory, and shell.

Answer

/etc/shadow

Answer

/etc/profile

Answer

/etc/group

Question 4

A user's account has been compromised. Which command is the most effective way to lock the user account immediately while preserving their files?

Accepted Answer

usermod -L jdoe. The usermod -L command locks the password, preventing the user from logging in, while keeping the user's home directory and files intact.

Answer

userdel jdoe

Answer

killall -u jdoe

Answer

chsh -s /bin/false jdoe

Question 5

Which permission bit must be set on a directory to allow a user to enter the directory and access files within it?

Accepted Answer

Execute (x). The execute bit (x) on a directory allows a user to 'enter' or 'traverse' the directory to access its contents.

Answer

Write (w)

Answer

Sticky bit

Answer

Read (r)

Question 6

A user reports they cannot execute a script named 'deploy.sh' even though the file permissions are set to 644. What must you change to enable execution for the owner?

Accepted Answer

chmod 744 deploy.sh. Permission 644 (rw-r--r--) lacks the execute bit. Changing the mode to 744 (rwxr--r--) adds execution rights for the owner.

Answer

chmod 655 deploy.sh

Answer

chown u+x deploy.sh

Answer

chmod +w deploy.sh

Question 7

You are configuring a temporary directory where multiple users save files. To ensure that users can only delete their own files and not files created by others, what must you set?

Accepted Answer

chmod +t /tmp/shared. The sticky bit (represented by the 't' in the others permission field) restricts file deletion to the owner of the file, the directory owner, or root.

Answer

chown root /tmp/shared

Answer

chmod 777 /tmp/shared

Answer

umask 077

Question 8

You need to prevent a standard user from accidentally deleting a critical configuration file owned by root. Which command ensures the file cannot be modified or deleted even by the root user?

Accepted Answer

chattr +i file.conf. The chattr +i command sets the immutable attribute, which prevents any user, including root, from deleting, renaming, or modifying the file until the attribute is removed.

Answer

chown root:root file.conf

Answer

chmod 400 file.conf

Answer

umask 000

Question 9

Which command-line tool is used to display the groups a specific user belongs to?

Accepted Answer

groups. The 'groups' command lists all group memberships for a specified username.

Answer

id

Answer

listgroups

Answer

whoami

Question 10

You need to create a new group named 'audit'. Which command should you execute?

Accepted Answer

groupadd audit. The 'groupadd' command is the standard utility for creating a new group in Linux.

Answer

newgroup audit

Answer

useradd -g audit

Answer

addgroup audit

Question 11

You want to set a default umask of 027 for all users. Which file should you edit to apply this globally?

Accepted Answer

/etc/profile. /etc/profile is the system-wide configuration file executed for all users upon login, making it the appropriate place for global umask settings.

Answer

/etc/bashrc

Answer

/etc/passwd

Answer

~/.bash_profile

Question 12

You notice a file has permissions listed as '-rwsr-xr-x'. What does the 's' in the owner's position indicate?

Accepted Answer

The file is a setuid binary.. The 's' in the owner's field indicates the setuid bit is set, meaning the file runs with the privileges of the file owner rather than the user running it.

Answer

The file is a setgid binary.

Answer

The file is immutable.

Answer

The file is a sticky directory.

Question 13

You want to change the owner of 'data.txt' from 'user1' to 'user2' AND the group from 'group1' to 'group2' in one command. Which is correct?

Accepted Answer

chown user2:group2 data.txt. The chown command supports the syntax 'user:group' to change both owner and group simultaneously.

Answer

chown user2 -g group2 data.txt

Answer

chown user2 group2 data.txt

Answer

chown user2 data.txt && chgrp group2 data.txt

Question 14

To add a new user named 'guest' and set their home directory to '/home/guest', which command is correct?

Accepted Answer

useradd -m -d /home/guest guest. The 'useradd -m' flag creates the home directory, and the username is specified as the last argument.

Answer

usermod -d /home/guest guest

Answer

useradd -h /home/guest guest

Answer

addhome guest

Question 15

A file is owned by root and has permissions 600. What happens if a regular user tries to read this file?

Accepted Answer

Access is denied.. Permission 600 (rw-------) allows only the owner (root) to read or write. A regular user (not root) will be denied access (Permission denied).

Answer

The user is prompted for a password.

Answer

The user can only read but not write.

Answer

Access is granted.