Debian is known for its strong focus on security, offering various tools, policies, and practices to help users maintain secure systems. Here are some key aspects of Debian security:
- Debian has a dedicated Security Team responsible for timely updates and patches, ensuring that security vulnerabilities in packages are quickly addressed.
- The team releases updates via Debian Security Advisories (DSA). Users are encouraged to subscribe to the security mailing list or check advisories regularly.
- Debian has a separate security repository (
deb http://security.debian.org/ stable/updates) where security patches are delivered.
- Regularly running
apt-get update && apt-get upgrade ensures that the system receives the latest security patches.
¶ 3. Secure Boot and Secure UEFI
- Debian supports Secure Boot to ensure that only trusted code runs during the boot process.
- It can also use Unified Extensible Firmware Interface (UEFI) for secure boot environments, adding another layer of defense.
- Debian comes with AppArmor, a Mandatory Access Control (MAC) framework. It restricts programs’ capabilities with per-program profiles, providing additional security to services like web servers, databases, etc.
- Enable and configure AppArmor profiles for critical services to reduce their attack surfaces.
- Debian provides firewall tools like iptables or nftables to control network traffic and protect systems from unauthorized access.
- UFW (Uncomplicated Firewall) is also available as a user-friendly way to manage firewall rules.
- While AppArmor is the default, SELinux (Security-Enhanced Linux) is also available. It provides a more comprehensive policy framework, though it requires more complex setup and maintenance.
- Debian supports full-disk encryption using LUKS (Linux Unified Key Setup) during installation, which protects data at rest.
- OpenSSL and GnuPG are widely used in Debian for securing communications and encrypting files.
- Debian recommends configuring SSH for secure remote management:
- Use ssh-keygen to generate secure key pairs for authentication.
- Disable password-based logins in favor of key-based authentication.
- Limit SSH access by modifying
/etc/ssh/sshd_config to disable root logins and change the default SSH port.
- The
unattended-upgrades package allows Debian to automatically apply security updates without user intervention, ensuring that the system stays up to date with the latest patches.
- Debian provides hardening guidelines to secure the operating system and services further. Some key points include:
- Installing security hardening tools like
libpam-tmpdir, fail2ban, and rkhunter for intrusion detection and system hardening.
- Enforcing least privilege, minimizing services, and regularly auditing logs and services for unusual activity.