Firewall as a Service (FWaaS) Implementation Best Practices

Traditional Firewall vs. FWaaS

Below is a comparison table that will help you visualize the differences between legacy firewalls and FWaaS. Their inherent differences also influence how implementation approaches differ when rolling either of them out.

Traditional firewalls still have a place in security infrastructure, but you need to understand where they fit. Organizations that operate from a single location with predictable traffic patterns will find that on-prem hardware-based firewalls are still adequate for security. As cloud integration and hybrid environments become more commonplace, traditional firewalls start to fall short and struggle to match the capabilities of FWaaS.

Best Practices for FWaaS Implementation

Proper FWaaS implementation requires best practices to be followed so that common issues can be avoided during the initial rollout phases of a project. Businesses need to extract the maximum value from FWaaS deployments as soon as possible, and this is only achievable when best practices are implemented from the beginning of a project.

Assess Your Environment Before Migration

A thorough assessment of your current network infrastructure needs to be conducted before you can begin your migration to FWaaS. You will need to document items like existing firewall rules, application dependencies, and traffic flows. During this process, you should identify obsolete policies and ensure that they are not carried over to your FWaaS unless they are active and absolutely necessary. 

Overly permissive firewall configurations can be disastrous in the cloud, so you will need to ensure the relevance of your existing traditional firewall before applying everything to FWaaS. Compile a pre-migration checklist so that your teams can begin the process of documenting and querying your existing firewall rules.

This assessment should also map out your critical ports and protocols for business-critical applications and services. Any dependencies that could affect operations need to be understood and documented to prevent service disruptions as your traffic starts routing through your new FWaaS infrastructure.

Start with Non-Critical Applications

When you plan your FWaaS implementation, look at performing it in stages. Migrating the entire network at once could introduce issues if you haven’t accounted for every eventuality. Look at starting with non-critical applications, or a segment of users, in phases. This allows you to test configurations and identify unexpected issues while you refine policies and procedures without affecting production systems. 

Piloting your deployment with non-critical systems also reveals how the FWaaS performs and interacts with your environment. You can monitor traffic and look for anomalies as each application is migrated over, and it allows your security teams to get familiar with the management console and alerting mechanisms. It’s also a good opportunity to monitor the logging systems before business-critical assets are moved onto the FWaaS.

The pilot phase will allow you to validate the configuration plan that you mapped out while confirming your team’s readiness, all in controlled stages that will give you better control and awareness.

Enforce the Principle of Least Privilege

Securing your FWaaS involves multiple layers, and the principle of least privilege is one of the cornerstones of this effort. The “deny by default” stance avoids overly permissive rules, and needs explicit permission for access. This minimizes the attack surface and limits the potential for lateral movement if an attacker ever gains initial access. 

Avoid the temptation of implementing convenient “Allow All” rules that grant access across your FWaaS. Every rule needs to have a clear business justification, and it needs to be scoped as narrowly as possible. 

Least privilege also extends to administrative access, and must ensure that only authorized personnel have access to the configurations and features that are appropriate for their roles. Role-based access control (RBAC) is another concept that is pivotal in maintaining secure systems across the organization, as only authorized team members will have permission to change critical settings within your systems.

Define Clear and Granular Firewall Rules

Firewall rule design needs to be implemented with specificity in mind, and not broad generalities that allow for too much access. Granular rules give you the precision that is needed to control network traffic so that it aligns with your current policies. 

You should consider structuring your rules based on:

• Resources or Services: Create rules that protect specific assets. An example could be database access, where only applications and users requiring permissions to use those resources are able to. 
• User Groups: Access should match specific user roles or department responsibilities. For example, a marketing user should have access to the CRM system, but they have no reason to reach development servers. 
• Application Requirements: Define rules based on what each application needs to function properly. This will include specific ports and protocols, and not broad access, because it is more convenient.

Documentation also plays a big role in maintaining your FWaaS. It helps with troubleshooting and serves as an auditable resource. When every rule has a clear purpose, it is far easier to identify a misconfiguration or policy violation during an investigation.

Enable Advanced Security Features

FWaaS solutions offer far more than just simple packet filtering and access control. Look at your FWaaS and strengthen your security with these options:

• Intrusion Prevention System (IPS): This feature lets you detect and block known attack patterns and malicious threats in real time. 
• URL Filtering: Allows you to restrict access to malicious and inappropriate websites, or any site that is deemed unauthorized based on category or reputation.
• Deep Packet Inspection (DPI): Analyzes the content and not only the headers of data packets to identify threats that basic filtering would miss.
• SSL/TLS Inspection: Decrypts and inspects encrypted traffic to detect threats hidden in secure sessions. This is a vital feature as most web traffic is now encrypted.
• Anti-Malware Scanning: Scans traffic for malicious payloads on both uploads and downloads.

Be mindful that you don’t have to have every single feature enabled and configured for your initial launch. Start with basic coverage, and increase your protection features as your implementation matures.

Integrate with Existing Security Infrastructure

FWaaS is not a singular solution that operates on its own; look at integrating your existing security stack with your FWaaS for added visibility. Connect your FWaaS logs to your Security Information Event Management (SIEM) systems, and get a centralized overview of your current security posture. 

This combination is powerful because it gives you the ability to correlate events that occur within your FWaaS and other network activity. Suspicious activity is easier to detect when you can see multiple events that seem to be related to one another across systems. 

Integration with your Identity and Access Management (IAM) systems gives your FWaaS context on a user level. Policies can use group and user information as part of their filtering and access control, which offers more flexibility than relying on IP address-based enforcement. 

Set up clearly defined thresholds for alerting and incident response procedures so that the detailed logs that your FWaaS generates add value to your security operations, and not additional noise.