How to Clean Network Firewall Rules in Four Steps

Organizations must ensure appropriate security policies are in place to safeguard their investments and optimize their security effectiveness. However, with the expansion and increased complexity of networks, network operations teams face challenges managing numerous firewalls and network devices from multiple vendors. They must deal with fragmented infrastructure, functional silos, staffing concerns, decentralized management, and inconsistent policy enforcement.

In addition, Information Technology (IT) teams cannot fully leverage their existing firewall investments and may face compliance issues, audit failures, and cyberattacks. A Cybersecurity Insiders report revealed that 58% of organizations have more than 1000 firewall rules, and 18% have more than 5000 rules, indicating the complexity of managing firewall rule sets for many organizations.

As networks grow more complex, organizations continue to grapple with securing a vastly expanded hybrid attack surface. To effectively protect the organization, it is now more critical than ever to have robust and accurate security processes in place. Therefore, implementing best practices for firewall rules is essential for thriving in this new era of increased cybersecurity risks.

Firewall Clean-Up Benefits

Streamlining and optimizing firewall rules can have multiple benefits for organizations. First and foremost, a cleaned-up firewall can significantly enhance security by minimizing the attack surface and reducing the risk of unauthorized access, data breaches, and cyberattacks. An effective set of firewall rules can also significantly improve the organization's defense posture and protect against potential vulnerabilities.

In addition to improved security, firewall rule optimization and clean-up can lead to better performance. The firewall can process traffic more efficiently by eliminating redundant or outdated rules, reducing latency, and improving network throughput. This can result in faster and more reliable network communication, ultimately enhancing productivity.

Compliance is another critical aspect. Many organizations are subject to regulatory compliance requirements, and a cleaned-up firewall can help ensure compliance with these standards. By aligning firewall rules with regulatory requirements, organizations can reduce the risk of non-compliance, penalties, and fines. A clean firewall can also provide better audit trails and documentation, simplifying compliance reporting and demonstrating adherence to industry regulations.

Cleaning a network firewall involves several essential steps to ensure that the firewall is optimized for better security and performance. Here are four steps to clean a network firewall:

1. Clean up over-lapping rules: Review the firewall rules and eliminate any shadowed and redundant rules that serve the same purpose or allow/deny the same traffic. Eliminating these rules will help minimize the attack surface and reduce the risk of unauthorized access, data breaches, and cyberattacks.
2. Remove duplicate objects: Review the objects (e.g., IP addresses, port numbers, etc.) used in the firewall rules and remove any duplicates or unused objects. This helps streamline the firewall ruleset and prevents potential conflicts or misconfigurations.
3. Delete or disable unused rules: Delete or disable any firewall rules that are no longer needed or serve a legitimate business purpose. This will reduce clutter and complexity in the ruleset and guarantee that only necessary rules are active, improving overall firewall performance.
4. Refine partially used rules and objects: Following a least access approach, refine any firewall rules or objects that are only partially used or not optimized, such as rules with overly permissive settings or objects with unnecessary attributes. This ensures that rules and objects are configured for maximum security and efficiency.

To ensure the seamless integration of new rules and maintain an organized and effective network firewall, the implementation of Change Request Lifecycle Management is also crucial. This approach goes beyond relying solely on periodic clean-ups and emphasizes the importance of maintaining order on a continuous basis.

The process of maintaining a clean and optimized network firewall requires ongoing efforts, including regular review, optimization, and constant monitoring. By adhering to these proactive measures and consistently revisiting and fine-tuning the firewall rules, organizations can ensure that their firewall remains effective in maintaining a secure posture and protecting their networks from potential security threats.

Alastair Williams is Vice President, Worldwide Sales Engineering at Skybox Security.

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