User account security, SSH hardening, and basic system hardening practices for Linux servers.
35 cards · basic cards · AI-written, checked twice. Edit anything.
- What file stores user passwords with their hashes in Linux?
- /etc/shadow
- What command is used to safely edit the sudoers file?
- visudo
- What are the correct permissions for a private SSH key file?
- 600
- What SSH configuration option disables root login?
- PermitRootLogin no
- What command generates a new SSH key pair?
- ssh-keygen
- What SSH configuration option disables password-based authentication?
- PasswordAuthentication no
- What is the primary advantage of SSH key-based authentication over passwords?
- Cryptographic keys are more resistant to brute-force attacks and are stronger
- What file contains the list of authorized public keys for SSH access?
- ~/.ssh/authorized_keys
- What does umask control in file permissions?
- Default permissions applied to newly created files and directories
- What command sets password aging policies on a user account?
- chage
- What is the default SSH configuration file location?
- /etc/ssh/sshd_config
- What SSH configuration option limits the number of failed login attempts?
- MaxAuthTries
- What happens when a user account reaches its expiration date?
- The account is locked and the user cannot log in
- What file lists all user accounts on a Linux system?
- /etc/passwd
- What permissions should the /etc/shadow file have?
- 600 or 000, readable only by root