3 Ways to Get Started with Firewall Automation

Key Takeaways

• Firewall automation significantly enhances security by reducing manual errors and ensuring consistent enforcement of network security policies.
• Automated change management streamlines firewall rule updates, improving response times and minimizing the risk of security breaches.
• Centralized and automated firewall management simplifies compliance tasks and provides clear audit trails for regulatory requirements.
• Implementing effective firewall automation strategies helps maintain business continuity by minimizing disruptions caused by firewall changes.

Getting Started with Firewall Automation

There is no official starting point for getting into firewall automation. Specific challenges often spawn the required automations, making necessity an invaluable factor for getting started for yourself. Below are three methods to help you understand what firewall automation is and how it works. Each of these can be adopted on its own, or gradually implemented as part of a larger project.

Method #1: Automated “Housekeeping” (Policy Cleanup)

Firewall rules accumulate over time without regular reviews. Decommissioned applications and services may still have active access rules across your network, which can leave the door open for potential intrusions. Temporary exceptions that are configured in an emergency can also accumulate if proper cleanup procedures aren’t followed, again creating unnecessary risks. The end result is bloated firewall infrastructure with ambiguous policies that make auditing more difficult, and obscure genuine security risks.

Automating policy cleanup is one of the lowest-risk projects that you can get started with. The policies that you work on should not touch any active traffic flows, and they should be designed to flag and detect issues, not block them. The goal is to identify vestigial policies so that they can be cleaned up as part of a more targeted project.

Starting here is wise because it carries low operational risk to your systems. None of the rules that you flag with your automation will be changed without extensive review first. Teams that run their first automated policy audit usually find a substantial cross-section of their rules haven’t matched a single packet or been active for some time. This information alone is usually enough to get support for your project from leadership, allowing you to build on early successes.

There are three main benefits of automation at this level:

• Unused Rules: Automated tools identify firewall rules that haven’t logged any matches for extended periods of time, usually in the 90 to 180-day range. Automation flags these unused rules so you can be proactive, instead of waiting for an annual audit to uncover them. This approach keeps things tidy and easier to audit when the time comes.
• Shadowed Rules: A shadowed rule is one that will never get evaluated by the system because another rule higher up in the policy already covers the same traffic. These rules are dangerous in the sense that they give the illusion of control without actually doing anything. Automated tools can identify these rules easily, allowing your team to decide on the best course of action when it comes time to remove shadowed rules that serve no purpose.
• Duplicate Objects: You’ll sometimes hear the term “object sprawl”, where multiple entries for the same service, subnet, or host exist on the system, but with different names. This makes policies harder to manage, and can cause confusion when an object is removed, but access is still mysteriously present for that removed object. Automation deduplication intelligently identifies and consolidates these entries, and can reduce the size of the object library.

Method #2: Automate “Gatekeeping” (Change Requests)

One of the most common frustrations in enterprise IT is the firewall change request process. A developer needs a new application to reach a specific server, so they submit a ticket. That ticket goes into the queue, and it gets reviewed by the network team. They assess the risk, draft a rule, and wait for approval. Once approval has been granted, the change is scheduled and then finally implemented. The whole process can take days, slowing down development and deployment velocity.

Automating the change request workflow doesn’t bypass the security review; that is still a vital part of the firewall management process. What does get automated are the parts of the review that don’t require human judgment, which removes most of the friction from the process.

This approach deals with some of the biggest pain points that development and operations teams face, reducing time to access for legitimate requests. Automating change requests also creates an auditable documentation trail for every change, which is great for fitting in with existing compliance frameworks that have strict policy governance.

This automated workflow has three steps:

1. Request Intake: A user or a system submits an access request either through a web form or an API request. In the request will be a source, destination, port, and a business justification. Using structured input ensures that there are no ambiguous requests hitting the system and that all the required information is present for each submission.
2. Automated Risk Assessment:  An automation engine evaluates each request against pre-defined rules and change criteria, allowing it to determine potential change impact. The automated risk assessment should check if the change affects critical infrastructure, network segmentation policies, and the device compliance status of the requesting device. Low-risk changes that pass all the evaluations can usually be automatically advanced to the next step.
3. Rule Drafting and Approval Routing: Requests that pass the initial risk threshold need to be approved manually. To do this, the automation drafts the specific firewall rules and sends those details to an approver for further evaluation. This notification contains the full context for the change, along with a risk assessment. Some organizations configure automatic approvals for low-risk changes, while others have human reviewers assess requests that exceed the risk threshold before implementing the required changes.

Method #3: Automate the “Guard Duty”

The previous two methods focus on maintenance and the processing efficiency of requests. The third method is where firewall automation plays a role in active defense. By using dynamic threat response automation, firewalls can update their own enforcement rules in real time when a threat is detected. This means that there is no human intervention required for reviewing the alert or submitting the change.

When threat intelligence flags a known malicious IP address or finds suspicious activity from an internal host, the firewall can act within seconds. Preventative measures are put in place before any damage is done to your network, mitigating threats before your security team is aware of any issues. These changes can be configured to notify your SOC teams so that they can get eyes on the issue quickly, preventing further spread.

This method adds substantial value to your security stack, especially if you operate in an industry that experiences active threats with quickly escalating attacks. By automating threat response, you close the gap between your team and your attackers, potentially buying critical time to investigate alerts as they are generated. The main caveat is that this setup requires a great deal of thought before implementing, especially if the firewall is performing automatic blocking actions. It is always recommended that testing is done in a staging environment before deploying automation to live sites.

The two most beneficial scenarios for this method that have the most impact are:

• Blocking Malicious IPs via Threat Intelligence Feeds: By integrating the firewall with a live threat intelligence feed, newly discovered malicious IP addresses are automatically added to block lists across all of the designated enforcement points. When the intelligence engine identifies a command-and-control server or a new active threat actor’s infrastructure, the firewall engages immediately without needing to wait for the update to complete.
• Quarantining Infected Internal Hosts: When an endpoint detection system or network monitoring tool detects suspicious behavior on an internal device, it has some major defenses. Some of the behaviors that these tools watch out for are: unusual port scanning, lateral movement attempts, or unexpected outbound connections. Automated rules can exclude these devices automatically, limiting the blast radius of malware infections and ransomware while teams investigate.

Challenges and Best Practices for Getting Started

The “Fear of Breaking” Problem

Organizations are naturally hesitant to try new approaches. The primary concern is that there could be a misconfiguration that causes issues with legitimate traffic being blocked, or something going completely wrong and taking a region offline. These are valid concerns, but they shouldn’t stop the entire planning phase. Instead, concerns need to be raised and noted so that any plan that goes forward has clear objectives and a rollback plan.

The good news is that it is best practice to start in read-only or detection-only mode. Implementing this kind of plan allows your automation engine to identify what it would do under specific circumstances so that you can review each scenario. As you gain confidence with your configurations, you can slowly start approving the suggested actions until your entire team is satisfied with the flow of operations.

The main idea is that incremental adoption is the goal, not a 100% cutover into automation. Data must be gathered at every step of your project and compared with your initial plan to ensure that each objective is satisfied. During this phase, you will be vetting the automation engine’s responses and ensuring that each intended action aligns with your current strategies.

This approach supports firewall compliance requirements by creating a documented record that can be audited in the future, outlining policy decisions, objectives, and outcomes at every stage of the project.

The Silo Problem

Firewall management at an organizational level can sometimes lead to unintended friction between teams. If your networking teams own the firewalls, but security owns the automation tooling, it can lead to misaligned priorities and mismatched expectations. Different teams pursue different outcomes. Networking departments focus on uptime and performance, while security teams focus on compliance, safety, and access.

The project needs to be collaborative from the start, with all stakeholders agreeing on specific project milestones and requirements. The project scope needs clear definitions in place, such as these examples:

• What constitutes an unused rule
• What are the levels of risk criteria
• What behavioral actions trigger a host quarantine
• Which change requests require approval, and which teams handle each type

Success metrics need to be decided early on, so that when the firewall automations go live, all teams involved with the management and maintenance of firewall infrastructure can celebrate together with shared, completed objectives.