Network Hardening Guide for IT Professionals

What is Network Hardening?

Network hardening involves implementing measures such as configuring firewalls, securing remote access points, blocking unused network ports, removing unnecessary protocols, implementing access lists, and encrypting network traffic to mitigate unauthorized access and bolster the security of a network’s infrastructure.

This process involves identifying and addressing vulnerabilities in device management and configurations to prevent exploitation by malicious actors aiming to infiltrate the network.

What is the difference between patching and hardening?

Patching addresses specific vulnerabilities through updates or fixes, while hardening involves implementing proactive security measures to strengthen overall defenses and reduce the likelihood of successful attacks. Hardening and patching are both essential practices in cybersecurity to prevent security risks, but they serve different purposes.

What is the difference between hardening and configuration?

Hardening refers to a specific action taken on a system’s configuration, while configuration is a broader term that refers to the overall settings and parameters.

Configuration: is the basic setup of a system that will define how the system operates, behaves, and interacts with other systems. Configuration options can include things like:

• Enabled services and features
• User accounts and permissions
• Security settings (firewalls, passwords)
• Network settings

Hardening: adjusts a system’s configuration to make it more secure. It involves making deliberate changes to reduce vulnerabilities and minimize the potential attack surface. Here’s how hardening uses configuration:

• Disabling unnecessary services: This reduces the number of potential entry points for attackers. (Configuration change)
• Strengthening user authentication: This can involve requiring complex passwords or multi-factor authentication. (Configuration change)
• Limiting access permissions: This restricts what users can do on the system based on their role. (Configuration change)

Securing Network Devices

Your network is an ecosystem of interconnected devices, each playing a crucial role in enabling communication and data movement. When it comes to network security, it’s essential to consider every device within this ecosystem. Those devices are:

Network Devices: This includes routers, switches, firewalls, and intrusion detection/prevention systems (IDS/IPS).

Endpoints: These are the devices that connect to your network, such as laptops, desktops, servers, and mobile devices.

Wireless Networks: Secure your Wi-Fi. You significantly reduce the risk of unauthorized access and data breaches.

20 Network Security Best Practices

In the past, traditional network security methods like firewalls and access controls were effective because corporate networks were well-defined. However, with surge in cloud computing, mobile devices, and remote work, the landscape has shifted.

This evolution necessitates a rethinking of network security. To adequately protect modern networks, we must move beyond traditional approaches and adopt new security measures that align with these changes.

Network hardening checklist:

1. Perform a Network Audit: Conduct a thorough assessment of your network infrastructure to identify vulnerabilities, outdated devices, and misconfigurations.
2. User Education: Educate users about security best practices, such as strong password management, recognizing phishing attempts, and avoiding suspicious links or attachments.
3. Incident Response Plan: Develop and maintain an incident response plan outlining procedures for responding to security incidents, including containment, eradication, and recovery steps.
4. Regular Training and Drills: Provide regular training and conduct drills to test the effectiveness of your incident response plan and ensure that staff are prepared to respond effectively to security incidents.
5. Implement Firewalls: Implement robust security solutions such as firewalls, intrusion detection/prevention systems (IDPS), and antivirus software.
6. Disable File Sharing Features: Disable unnecessary file-sharing services or features on your network devices.
7. Regular Backups: Regularly back up critical data and configurations to ensure quick recovery in the event of a security incident or data loss.
8. Update Software and Firmware: Regularly update your antivirus and anti-malware software to detect and remove malicious code.
9. Secure Your Routers: Routers are critical components of your network. Change default passwords, disable remote management, and keep router firmware updated.
10. Use a Private IP Address: Assign private IP addresses to internal devices. This prevents direct exposure of internal systems to the internet.
11. Access Control Lists (ACLs): Implement ACLs to control and restrict access to network resources based on user identity, device type, or other criteria.
12. Network Security Maintance: Regularly monitor and maintain your network security by patching vulnerabilities promptly, reviewing logs, and addressing security incidents.
13. Network Segmentation: Divide your network into segments based on function (e.g., production, development, guest). Apply access controls to limit communication between segments.
14. Network Monitoring: Implement robust network monitoring tools to detect and respond to suspicious activity or unauthorized access attempts in real-time.
15. Secure Remote Access: Secure remote access to the network using VPNs or other secure methods, and enforce strong authentication mechanisms for remote users.
16. Zero Trust Principles: Adopt a zero-trust approach where every user and device is treated as untrusted until verified.
17. Regular Security Audits: Conduct periodic security audits and assessments to evaluate the effectiveness of your network security measures and identify areas for improvement.
18. Network Documentation: Maintain detailed documentation of your network architecture, configurations, and security policies to facilitate troubleshooting and ensure consistency in security practices.
19. Vendor Security: Ensure that third-party vendors and suppliers adhere to security best practices and conduct regular security assessments of their products and services used in your network.
20. Continuous Improvement: Continuously monitor and evaluate your network security posture, and adapt your security measures to address evolving threats and vulnerabilities.

Service Security Recommendations

One of the key aspects of network hardening is patching and updating network devices and software-based systems regularly. This helps prevent bad actors from exploiting known vulnerabilities to gain access to the network. Additionally, monitoring network traffic and enforcing strict remote access policies can further enhance network security posture.

The National Security Agency (NSA) states all unnecessary services should be disabled. They list disabling:

• Echo Protocol: A legacy protocol to measure the round trip time of a packet.
• Chargen Protocol: A legacy protocol that uses arbitrary characters to test, debug, and measure the connection.
• Discard Protocol: A legacy protocol to simply discard received packets.
• Daytime Protocols: Returns ASCII character strings of the current date and time.
• FTP Protocol: Allows users to copy files between their local system and any system that can be reached on the network.
• Telnet: An application layer clear text protocol used on the network to communicate with another device.
• BootP Service: A legacy protocol used to assign an IP address to a device.
• HTTP Server: Most devices come with a Web service enabled by default.
• SNMP Protocol: A protocol to manage network devices. If needed, only run SNMPv3 with a Management
• Information Base (MIB) allow list ("Reducing the risk of Simple Network Management Protocol SNMP Abuse" 1) and do not use SNMP community strings.
• Discovery Protocols: These protocols are used to share information with neighboring devices and discover the platform of those devices.
• IP Source Routing: Allows the sender to control the route of information to the destination.
• IP Unreachable: Internet Control Message Protocol (ICMP) messages can be used to map out the network topology.
• IP Mask Reply: Replies respond to ICMP mask requests by sending out ICMP mask replies containing important network information.
• Zero Touch Provisioning: Zero touch provisioning allows network devices to reach out to download firmware and configurations without any user interaction.

Hardening Process

Automating network security offers a powerful solution to bolster overall defenses by simplifying and accelerating the deployment of hardening measures.

The hardening process involves implementing access controls, such as multi-factor authentication, to strengthen network access points and safeguard users’ data.

By focusing on network hardening standards, organizations can effectively limit the opportunities for cyber attacks and protect sensitive data from unauthorized access. This proactive approach is essential in today’s threat landscape, where bad actors continually seek to exploit vulnerabilities for malicious purposes. Through comprehensive network hardening efforts, organizations can strengthen their defenses and ensure a more secure network environment for their users and data.