How to Harden Ubuntu 24.04 Server Security in 2026: Complete Guide

Securing your Ubuntu 24.04 server is critical in 2026, especially with increasing cyber threats targeting Linux infrastructure. This comprehensive guide shows you exactly how to harden Ubuntu 24.04 server security with proven, step-by-step methods that protect your system from unauthorized access, malware, and data breaches.

Whether you’re running a production web server, database, or development environment, implementing these Ubuntu 24.04 server security best practices will significantly reduce your attack surface and keep your infrastructure safe.

Why Ubuntu 24.04 Server Security Matters

Ubuntu 24.04 LTS (Long-Term Support) brings significant security improvements, including Linux kernel 6.8 with enhanced security mitigations, updated OpenSSH and OpenSSL versions, and improved AppArmor profiles. However, default installations still require hardening to achieve enterprise-grade Ubuntu 24.04 server security.

Recent security statistics show that 70% of successful server breaches exploit weak SSH configurations, outdated packages, or misconfigured firewalls—all preventable with proper Ubuntu server security hardening. Let’s implement these protections now.

Step 1: Initial System Hardening and User Configuration

The foundation of Ubuntu 24.04 server security starts with proper user management and SSH configuration. Never use the root account directly—always use

sudo for administrative tasks.

Create a Non-Root Administrative User

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# Create new user with sudo privileges

sudo adduser secureadmin

sudo usermod -aG sudo secureadmin



# Test sudo access

su - secureadmin

sudo whoami  # Should return 'root'

This establishes accountability and limits the blast radius of compromised credentials. Every administrative action is logged with the user’s identity, essential for Ubuntu 24.04 server security auditing.

Step 2: SSH Hardening for Ubuntu 24.04

SSH is the primary attack vector for Linux servers. Implementing SSH hardening Ubuntu 24.04 protections is your first line of defense against brute-force attacks and unauthorized access.

Disable Password Authentication and Root Login

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# Edit SSH configuration

sudo nano /etc/ssh/sshd_config



# Apply these security settings:

PermitRootLogin no

PasswordAuthentication no

PubkeyAuthentication yes

ChallengeResponseAuthentication no

UsePAM yes

X11Forwarding no

AllowUsers secureadmin



# Restart SSH service

sudo systemctl restart sshd

Before disabling password authentication, ensure you have SSH keys properly configured. Generate a key pair on your local machine:

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# On your local machine (not the server)

ssh-keygen -t ed25519 -C "[email protected]"

ssh-copy-id secureadmin@your-server-ip

This approach eliminates password-based attacks entirely, a critical step in hardening Ubuntu 24.04 server security. The Ed25519 algorithm provides excellent security with small key sizes.

Change Default SSH Port (Optional but Recommended)

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# In /etc/ssh/sshd_config, change:

Port 2222  # Use any port between 1024-65535



# Update firewall before restarting SSH

sudo ufw allow 2222/tcp

sudo systemctl restart sshd

While security through obscurity isn’t a replacement for strong authentication, changing the default port 22 reduces automated bot attacks by 95%, according to server security studies. For more Linux security tips, see our guide on securing NFS shares in Linux.

Step 3: Configure UFW Firewall for Ubuntu 24.04

Ubuntu’s Uncomplicated Firewall (UFW) provides essential network-level protection. Proper firewall configuration Ubuntu 24.04 blocks all unnecessary traffic by default.

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# Enable UFW with deny-by-default policy

sudo ufw default deny incoming

sudo ufw default allow outgoing



# Allow SSH (use your custom port if changed)

sudo ufw allow 2222/tcp



# Allow HTTP and HTTPS for web servers

sudo ufw allow 80/tcp

sudo ufw allow 443/tcp



# Enable firewall

sudo ufw enable



# Check firewall status

sudo ufw status verbose

This configuration implements the principle of least privilege—only explicitly allowed services can receive inbound connections. Every production Ubuntu 24.04 server should have UFW enabled as baseline protection.

Step 4: Automatic Security Updates with Unattended-Upgrades

Outdated packages are the #1 cause of server compromises. Configure automatic security updates to maintain Ubuntu 24.04 server security without manual intervention.

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# Install and configure unattended-upgrades

sudo apt update

sudo apt install unattended-upgrades

sudo dpkg-reconfigure --priority=low unattended-upgrades



# Verify configuration

sudo nano /etc/apt/apt.conf.d/50unattended-upgrades

Ensure these lines are uncommented:

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"${distro_id}:${distro_codename}-security";

//"${distro_id}:${distro_codename}-updates";

This automatically installs security patches from Ubuntu’s security repository, keeping your system protected against known vulnerabilities. You can verify pending updates with:

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ubuntu-security-status

sudo apt list --upgradable

For additional security configuration tips, check our guide on running secure shell scripts in Linux.

Step 5: Implement Fail2Ban for Intrusion Prevention

Fail2Ban monitors log files and automatically blocks IP addresses showing malicious behavior. This is essential Ubuntu 24.04 intrusion prevention that stops brute-force attacks before they succeed.

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# Install Fail2Ban

sudo apt install fail2ban



# Create local configuration

sudo cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local

sudo nano /etc/fail2ban/jail.local

Configure SSH protection (adjust port if you changed it):

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[sshd]

enabled = true

port = 2222

filter = sshd

logpath = /var/log/auth.log

maxretry = 3

bantime = 3600

findtime = 600

This configuration bans any IP address that fails 3 SSH login attempts within 10 minutes, for 1 hour. Adjust these values based on your security requirements.

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# Restart Fail2Ban

sudo systemctl restart fail2ban



# Check banned IPs

sudo fail2ban-client status sshd

Step 6: Enable AppArmor for Mandatory Access Control

AppArmor provides Linux kernel security module that restricts program capabilities. Ubuntu 24.04 ships with AppArmor enabled by default, but you should verify and optimize profiles.

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# Check AppArmor status

sudo aa-status



# View profiles

sudo aa-enforce /etc/apparmor.d/*



# Install additional profiles

sudo apt install apparmor-profiles apparmor-profiles-extra

AppArmor limits what actions processes can take, even if compromised. For example, a web server process can’t access system files outside its designated directory, significantly improving Ubuntu 24.04 server security.

Step 7: Configure Password Policies with PAM

Even with SSH key authentication, local accounts need strong password policies for console access and sudo operations.

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# Install password quality checking

sudo apt install libpam-pwquality



# Configure password requirements

sudo nano /etc/security/pwquality.conf

Recommended settings:

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minlen = 12

minclass = 3

maxrepeat = 2

reject_username

enforce_for_root

This enforces 12-character minimum passwords with at least 3 character classes (uppercase, lowercase, digits, special). Configure account lockout after failed attempts:

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# Edit PAM common-auth

sudo nano /etc/pam.d/common-auth



# Add this line:

auth required pam_faillock.so preauth silent deny=5 unlock_time=1800

This locks accounts after 5 failed attempts for 30 minutes, preventing brute-force attacks on local authentication.

Step 8: Implement System Auditing with Auditd

The Linux Audit Framework (auditd) tracks security-relevant system events, crucial for compliance and forensic analysis.

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# Install auditd

sudo apt install auditd audispd-plugins



# Enable and start service

sudo systemctl enable auditd

sudo systemctl start auditd



# Add audit rules for critical files

sudo nano /etc/audit/rules.d/audit.rules

Essential audit rules for Ubuntu 24.04 server security:

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# Monitor /etc/passwd changes

-w /etc/passwd -p wa -k passwd_changes



# Monitor /etc/group changes

-w /etc/group -p wa -k group_changes



# Monitor sudo commands

-w /etc/sudoers -p wa -k sudoers_changes



# Monitor SSH key directory

-w /root/.ssh -p wa -k root_ssh_keys

Reload audit rules and check status:

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sudo augenrules --load

sudo auditctl -l

Step 9: Disable Unnecessary Services

Every running service is a potential attack vector. Minimize your attack surface by disabling unused services.

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# List all running services

systemctl list-units --type=service --state=running



# Disable unnecessary services (example)

sudo systemctl disable bluetooth.service

sudo systemctl stop bluetooth.service



# Remove unnecessary packages

sudo apt purge snapd  # If not using snaps

sudo apt autoremove

Only keep services you actively use. A minimal web server typically only needs SSH, HTTP/HTTPS, and your web server service running.

Step 10: Regular Security Monitoring and Maintenance

Security isn’t a one-time setup—it requires ongoing monitoring. Implement these practices:

Daily Security Checks

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#!/bin/bash

# Save as /usr/local/bin/security-check.sh



echo "=== Ubuntu 24.04 Security Status ==="

echo ""



echo "Failed Login Attempts:"

sudo grep "Failed password" /var/log/auth.log | tail -10



echo ""

echo "Fail2Ban Status:"

sudo fail2ban-client status sshd



echo ""

echo "Pending Security Updates:"

apt list --upgradable 2>/dev/null | grep security



echo ""

echo "Disk Usage:"

df -h /



echo ""

echo "Active Connections:"

sudo ss -tuln | grep LISTEN

Make it executable and run daily via cron:

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sudo chmod +x /usr/local/bin/security-check.sh

sudo crontab -e

# Add line:

0 8 * * * /usr/local/bin/security-check.sh | mail -s "Daily Security Report" [email protected]

Advanced Ubuntu 24.04 Security Techniques

1. Two-Factor Authentication for SSH

Add an extra security layer with Google Authenticator:

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sudo apt install libpam-google-authenticator

google-authenticator



# Edit /etc/pam.d/sshd

auth required pam_google_authenticator.so



# Edit /etc/ssh/sshd_config

ChallengeResponseAuthentication yes

AuthenticationMethods publickey,keyboard-interactive

2. Disk Encryption with LUKS

For sensitive data, implement full disk encryption during installation or encrypt specific partitions:

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# Check LUKS encryption status

sudo cryptsetup status /dev/mapper/ubuntu--vg-root

3. Network Intrusion Detection with AIDE

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# Install AIDE (Advanced Intrusion Detection Environment)

sudo apt install aide aide-common



# Initialize database

sudo aideinit

sudo mv /var/lib/aide/aide.db.new /var/lib/aide/aide.db



# Run check

sudo aide --check

Security Checklist for Ubuntu 24.04 Server

Use this checklist to verify your Ubuntu 24.04 server security hardening:

• ✅ Created non-root administrative user with sudo access
• ✅ Disabled root SSH login and password authentication
• ✅ Configured SSH key-based authentication
• ✅ Changed SSH port from default 22 (optional)
• ✅ Enabled UFW firewall with deny-by-default policy
• ✅ Configured automatic security updates (unattended-upgrades)
• ✅ Installed and configured Fail2Ban for intrusion prevention
• ✅ Verified AppArmor is active and enforcing
• ✅ Implemented strong password policies with PAM
• ✅ Enabled system auditing with auditd
• ✅ Disabled unnecessary services and removed unused packages
• ✅ Set up regular security monitoring and reporting
• ✅ Configured secure backups (off-site, encrypted)
• ✅ Documented all security configurations

Common Ubuntu 24.04 Security Mistakes to Avoid

Even experienced administrators make these errors when securing Ubuntu 24.04 servers:

1. Not testing SSH keys before disabling password auth – Always verify SSH key login works before locking yourself out
2. Forgetting to update firewall after changing SSH port – Update UFW rules before restarting SSH
3. Ignoring security updates – Configure unattended-upgrades or check manually daily
4. Using weak sudo passwords – Even with SSH keys, sudo password must be strong
5. Not backing up before major changes – Always snapshot or backup before security configuration changes
6. Overlooking log monitoring – Security tools are useless if you don’t review logs regularly

For more Linux administration tutorials, explore our comprehensive guides on rebooting Linux from terminal and mounting USB drives in Linux.

Ubuntu 24.04 vs 22.04 Security Improvements

Ubuntu 24.04 LTS introduces several security enhancements over 22.04:

• Linux Kernel 6.8 – Improved security mitigations, better hardware support
• OpenSSH 9.6 – Enhanced cryptographic algorithms, removed legacy ciphers
• OpenSSL 3.0 – Modern TLS support, FIPS 140-3 compliance readiness
• Updated AppArmor profiles – Better default protection for system services
• systemd 255 – Improved sandboxing capabilities for services
• nftables backend for UFW – More efficient firewall performance

These improvements make Ubuntu 24.04 server security stronger out-of-the-box compared to previous releases, but proper hardening remains essential.

Additional Security Resources

For deeper Ubuntu 24.04 security knowledge, consult these authoritative resources:

• Ubuntu Official Security Documentation – Canonical’s comprehensive security guide
• CIS Ubuntu Linux 24.04 Benchmark – Industry-standard hardening checklist
• Ubuntu Security Notices (USN) – Latest security advisories and patches

Conclusion: Maintaining Ubuntu 24.04 Server Security

Implementing comprehensive Ubuntu 24.04 server security hardening requires systematic configuration across multiple layers—user management, network security, access control, monitoring, and ongoing maintenance. By following this guide, you’ve implemented enterprise-grade security controls that dramatically reduce your server’s attack surface.

Remember that security is an ongoing process, not a one-time setup. Schedule regular security audits, stay current with Ubuntu security notices, review logs daily, and update your configurations as new threats emerge. With these practices in place, your Ubuntu 24.04 server will remain secure throughout its LTS lifecycle through 2029.

The investment in proper Ubuntu server security pays dividends in reduced breach risk, compliance readiness, and peace of mind. Start implementing these hardening techniques today—your future self will thank you when automated attacks bounce harmlessly off your properly secured server.

• About the Author
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Mark

Mark is a senior content editor at Text-Center.com and has more than 20 years of experience with linux and windows operating systems. He also writes for Biteno.com

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