Firewall rule
cleanup & performance optimization tool

Over the years, your firewalls have accumulated thousands of rules and objects; and many of these rules are now out-of-date or obsolete.

Bloated rulesets not only add complexity to daily tasks such as change management, troubleshooting, and auditing, but they can also impact the performance of your firewall appliances, resulting in decreased hardware lifespan and increased TCO.

You should periodically review your firewall rule-bases to identify and discard outdated, duplicate, or contradictory rules. Rule cleanup and optimization improve network security, boost firewall performance, and help you meet regulatory standards such as PCI DSS and GDPR.

Safely removing rules, however, is not easy, as it may cause service outages. Periodic rule recertification projects are time-consuming and complex – with multiple teams trying to understand why rules were created in the first place.

In this article, you will learn firewall rule optimization and cleanup best practices. You will also learn how a firewall management tool can help you automate policy management, auditing, usage analysis, and other firewall management tasks – enabling you to streamline workflows, find outdated rules, meet compliance requirements, identify misconfigurations, and catch vulnerabilities.

Firewall rules determine the network traffic allowed in and out of your network. When the rules are up to date and properly configured, they keep your network secure. What happens when the rules are outdated?

Slow firewall performance: Redundant or duplicate rules negatively impact firewall performance significantly, making it sluggish. This happens because the firewall has to process and maintain more rules than necessary. The firewall performs work that does not contribute to the actual security of your network due to rule redundancy.

Rule management becomes more complex: Unused firewall rules and duplicate objects take up space and increase the complexity of firewall administrators’ management tasks. Network operators invest time and resources trying to maintain rules that are of no use to the security of the network. Unnecessary rules complicate firewall security controls – leading to various security management challenges.

Major security risks: Misconfigured, expired, or outdated rules pose significant security risks. Misconfigured rules cause rules to malfunction, enabling malicious actors to infiltrate your network. In addition to making rule management more complex, redundant rules create security risks by possibly opening a port or VPN tunnel.

Expired or outdated rules create vulnerable entry points. Rules that are not aligned with current security requirements, traffic patterns, and best practices, are unable to identify the latest attack techniques. As a result, hackers can exploit expired rules to gain access to your network.

Shadowed rules can override all other critical rules, while conflicting rules can create backdoor entry points.

Compliance issues: Having outdated rules makes networks prone to security breaches. This is a major security red flag that most data security regulatory agencies cannot fail to notice.

In addition, outdated rules bloat rulesets and make it very difficult to comply with standards. They increase the complexity of firewall management tasks such as auditing and rule cleanup. This creates compliance issues when performing auditing for the purpose of verifying compliance with regulatory requirements.

Troubleshooting challenges: When an issue occurs, network operators troubleshoot to identify the root cause and possibly plug the loophole. One of the critical parts of troubleshooting is a review of rule-bases. Redundant rules add to the complexity of the troubleshooting process. This leads to a waste of time and financial resources.

The first stage of firewall cleanup is policy auditing. Auditing your existing firewall policies enables you to know the redundant rules and learn what each active rule does. Take the following steps to assess your firewall rule-bases.

Step 1: Review access control – Access-control policies contain parameters that define conditions for network access. The conditions or criteria must be met before a certain part of the network can be accessed. Review access control and make the changes necessary for implementing industry-standard rule cleanup.

Step 2: Assess automation rules – Review automation rules and document accordingly. Assessing automation rules helps administrators find rules that need optimization or deletion.

Step 3: Review unnecessary policies – Unnecessary policies are rules that are no longer needed or relevant. Assess your rule-bases to find rules that are no longer useful. Analyze them to determine whether some of them should be optimized. Isolate the ones that are no longer needed and should be removed.

Step 4: Review external devices and routers – Assess your external devices and routers to ensure they are in good shape.

Step 5: Audit firewall devices – For your firewall to perform optimally, the hardware and software parts must work in synergy. As you implement a series of revisions, give attention to the hardware components of your firewall system. Examine firewall devices to ensure they are not faulty or compromised.

Step 6: Modify policies – The major purpose of a policy audit is to reinforce and optimize some rules, and remove those that are no longer needed. To improve performance and ward off security threats, modify policies to align with current security requirements and best practices.

After auditing your firewall policies, the next phase is to implement the cleanup process. Here’s how to properly perform a firewall cleanup:

Consolidate duplicate/redundant rules: Identify duplicate or redundant rules and consolidate them with proper documentation. This makes it easier to get rid of them – without mistakenly involving desired rulesets.

Remove unnecessary rules: Delete the rules that are no longer necessary. This frees up your rule-bases and lets you focus on maintaining and managing policies that are relevant to your current security posture.

Remove misconfigured rules: Get rid of misconfigured rules or incorrect rules that contain typographic or specification errors.

Delete outdated rules: Remove obsolete rules that you do not want to update or optimize, to suit your current security needs.

Re-organize rule order: After removing unnecessary and outdated rules, you need to inspect and re-order the rules to ensure no loopholes are left open.

Optimize rule efficiency: Perform policy analysis to identify rulesets that need to be optimized. You can achieve this by either introducing new rules or strengthening existing rules.

Document and maintain rule changes: Document the changes you make. Proper documentation is necessary for future reference. To maintain rule changes, admins need documents, such as rule reports, that clearly define what each rule does and why it was configured.

Test and validate rules: Validate the efficiency of the rules to ensure everything is working as expected. You can achieve this by routing traffic through the firewall to assess the authentication process and ensure the rules work properly.

The cybersecurity landscape is volatile, unpredictable, and fast-changing. To stay ahead of malicious cyber actors, you need to implement new firewall policies from time to time. This security approach helps you prevent security breaches with up-to-date firewall rulesets.

While implementing new policies, strive to create rules that align with current security requirements and best practices. Take care to properly document all your policy changes for future reference. In addition, take note of the following firewall optimization best practices.

Limit the number of rules

Do not make your firewall policies more complicated than necessary. In this case, less can be more. Limit the number of rules to the minimum you need to keep your network secure. Creating more rules than necessary increases the complexity of firewall management tasks such as auditing, change management, and troubleshooting.

Additionally, creating too many rules increases the chances of accumulating outdated, duplicate, or redundant rules over time. Keep your rulesets simple, comprehensive, and efficient. Regularly analyze your security needs and implement firewall rules that are just enough to keep your network safe.

Regularly review and update the rule-base

Review the rule-base regularly according to your security needs. Regular assessment enables you to identify configuration gaps or issues that could lead to a security breach. As the threat landscape keeps changing, you need to review and update the rule-base to meet evolving security requirements and best practices.

Lack of regular review and policy optimization is what leads to the accumulation of outdated, redundant, misconfigured, or duplicate rules. Assessing your rule-base as frequently as necessary helps you maintain ‘clean’ firewall rules that are optimized for maximum security.

Enforce a “least privilege” principle

The least privilege principle is an information security concept that maintains that an employee or a user should be allowed access only to the specific data, capability, and resources needed to complete a given task. This means that access to resources is strictly regulated. Users are only allowed to access what they need to accomplish their tasks.

This concept improves accountability and reduces the chances of a security breach due to human error. When employees are given the privilege to operate or access every aspect of the network, they are likely to overstep or abuse the privilege – leading to disastrous security mistakes.

Segment networks to reduce the scope of rules

Apply the principle of micro-segmentation. This concept entails breaking your network into smaller segments and applying security controls independently to each micro-segment. Micro-segmentation boosts security and gives better control over log data and risk management.

Segmentation reduces the scope of rules, attack surface area, and scope of damage of a single breach. When a set of rules is compromised, it only affects the segment of the network to which the rules apply – as opposed to affecting the entire network.

With security policies applied separately to each segment, a company-wide breach is unlikely. When something goes wrong, restoring compliance is easier since security controls are not lumped together.

Test and validate rules before implementing changes

To avoid deploying rules that are not properly configured, test and validate rules before implementing changes. Effecting changes without proper testing and validation can introduce vulnerable points in your network.

Do not assume new rules are efficient. Go one step further and validate them before deploying changes. Evaluate rule efficiency using data packets with various SSH, TCP, UDP, and IP address parameters.

AlgoSec, a global cybersecurity leader, enables you to optimize your firewall policy effortlessly and keep it clean and lean. It provides actionable reports and real-time visibility across your hybrid network, enabling you to remove the bloat and clutter from your policy.

AlgoSec’s intelligent automation of change management processes ensures that new rules are optimally designed and implemented so that you do not generate more clutter over time. With a flexible, affordable pricing model, AlgoSec helps you to:

• Uncover and remove unused, duplicate, or conflicting rules

• Consolidate or reorder rules for better performance

• Tighten overly permissive rules (e.g. “Any/Any”) without impacting business requirements

• Recertify expired rules based on security and business needs

• Maintain policy hygiene by intelligently designing each rule change

• Securely remove access for decommissioned applications

• Ensure a clean and optimized security policy

• Drastically reduce complexity across the firewall estate

• Streamline the audit preparation processes

• Ensure continuous compliance

• Avoid outages and prevent cyber-attacks

• Improve network performance and extend the firewall hardware lifespan