Linux+ Security Quiz: Can You Master Permissions, SELinux & More?

1. What is the purpose of the /etc/sudoers file?

Store sudo command history

Define which users can run sudo and what commands they can execute

List all system processes running with elevated privileges

Configure password aging policies

2. What does disabling root login via SSH accomplish?

Prevents direct root access attempts, improving security through forced privilege escalation

Removes all administrative capabilities from the system

Enables automatic password changes

Encrypts all network traffic

3. Which file stores group membership information including secondary groups?

/etc/passwd

/etc/group

/etc/shadow

/etc/members

4. What is the purpose of the chroot environment in Linux security?

Isolate a process to a restricted filesystem, limiting access to system resources

Encrypt all user data automatically

Monitor all user login attempts

Disable network connectivity for security

5. Which command is used to set or modify ACLs on a file?

Setfacl

Getfacl

Chmod +a

Chacl

6. In ACLs (Access Control Lists), what additional flexibility do they provide over standard permissions?

Allow multiple users and groups specific permissions beyond owner/group/other

Enable SELinux enforcement

Prevent all access to files

Encrypt file contents automatically

7. Which command changes a user's password expiration settings?

Passwd -e

Chage

Usermod -p

Shadow -x

8. What does the umask value control?

Default file and directory permissions for newly created files

Maximum number of open files per user

Time limit for user sessions

Password expiration settings

9. Which authentication method is most secure for remote SSH access?

Password authentication

Public key authentication with a passphrase

Empty password

Root login with a simple password

10. In Linux, a user's primary group is determined by which file?

/etc/group

/etc/passwd

/etc/shadow

/etc/gshadow

11. In Linux file permissions, what does the execute (x) permission allow on a directory?

Run scripts stored in that directory

List and access files within that directory

Modify file contents in that directory

Delete files from that directory

12. Which command displays the current SELinux context of a file?

Ls -Z

Ls -l

Stat -S

Getenforce

13. What does the sticky bit (t) on a directory prevent?

Users from deleting files they don't own

Users from reading files in that directory

Group members from accessing the directory

The owner from modifying permissions

14. Where are encrypted password hashes stored in a secure Linux system?

/etc/passwd

/etc/shadow

/etc/crypt

/etc/secure

15. Which file stores user account information including usernames and UIDs?

/etc/passwd

/etc/shadow

/etc/group

/etc/sudoers

16. What does sudo allow a non-root user to do?

Run commands with superuser privileges without entering the root password

Permanently become the root user

Bypass SELinux policies

Access any file without authentication

17. Which SELinux component defines rules that allow or deny access based on context?

Policy

Subject

Object

Attribute

18. In SELinux, what is the default enforcing mode that blocks unauthorized access?

Permissive

Enforcing

Disabled

Audit-only

19. What does the setuid (SUID) bit allow a program to do?

Run with owner's file permissions, not the user's

Grant group ownership to all users

Set a sticky bit on directories

Restrict file access to the owner only

20. Which command sets a file's permissions to 755 (rwxr-xr-x)?

Chmod 755 filename

Chmod 644 filename

Chmod 777 filename

Chmod 700 filename

Linux+ Security Quiz: Can You Master Permissions, SELinux & More?

1. What is the purpose of the /etc/sudoers file?

2.

What first name or nickname would you like us to use?

2. What does disabling root login via SSH accomplish?

3. Which file stores group membership information including secondary groups?

4. What is the purpose of the chroot environment in Linux security?

5. Which command is used to set or modify ACLs on a file?

6. In ACLs (Access Control Lists), what additional flexibility do they provide over standard permissions?

7. Which command changes a user's password expiration settings?

8. What does the umask value control?

9. Which authentication method is most secure for remote SSH access?

10. In Linux, a user's primary group is determined by which file?

11. In Linux file permissions, what does the execute (x) permission allow on a directory?

12. Which command displays the current SELinux context of a file?

13. What does the sticky bit (t) on a directory prevent?

14. Where are encrypted password hashes stored in a secure Linux system?

15. Which file stores user account information including usernames and UIDs?

16. What does sudo allow a non-root user to do?

17. Which SELinux component defines rules that allow or deny access based on context?

18. In SELinux, what is the default enforcing mode that blocks unauthorized access?

19. What does the setuid (SUID) bit allow a program to do?

20. Which command sets a file's permissions to 755 (rwxr-xr-x)?