The threat landscape doesn’t hold still, and firewall security has to keep adapting right along with it. That’s why banks and credit unions should be evaluating their security processes and firewall rules on a regular basis, quarterly, at minimum.

Why Firewall Reviews Matter

Firewalls have been part of network security for more than 25 years now, monitoring outgoing and incoming traffic and serving as an institution’s first line of defense: preventing unauthorized access and blocking specific communications based on the security settings in place.

Having a firewall in place isn’t enough on its own, though. Banks and credit unions are constantly adding new services and changing business processes, and a firewall configuration that isn’t checked regularly leaves an institution open to attacks and breaches it never sees coming. Regular reviews are what catch a weakness before it gets exploited, and they let rules get updated as technology changes or new threats emerge.

There’s a regulatory reason to do this quarterly too. The FFIEC Cybersecurity Assessment Tool sets the quarterly Firewall Audit as a baseline standard: an institution that can’t answer “yes” to it hasn’t met the baseline requirements for Domain 3 of the CAT. That same quarterly audit shows up in the FFIEC Information Security Booklet as well.

Where to Start with Quarterly Firewall Rule Evaluations

Assessing firewall rules well starts with a few basic areas.

Start with a solid understanding of how the firewall actually works and how it’s set up. Regular firewall reports should be coming in too, and they’re worth reading carefully, not just filing away.

What to Look for in Firewall Rules

Knowing how to actually review or audit firewall rules is its own challenge. Four basic things help guide the process:

1. Evaluate the firewall’s change management procedures. This confirms that every past rule change was logged properly and that the right procedures were actually followed.
2. Compare current firewall rules against previous ones. This makes changes easy to spot, lets an institution track exactly what changed and confirm whether each change was actually necessary, and it surfaces unused or “stale” rules that should have been retired already.
3. Evaluate the external IP addresses the firewall allows. Confirm they’re still safe and still make sense for the institution to be using. An address that looks odd or out of place is usually a sign the rule needs to change.
4. Confirm there’s still a real business need for every open port. Firewall rules often keep ports open for external communication, and checking whether that need still exists is a basic step, but an important one. If it doesn’t, the rule can be deleted and that unnecessary communication path closed.

Firewall rule reviews can be done manually, but that takes real time, and it comes at a real cost in operational resources and personnel. That’s why a lot of institutions bring in outside help for this work. It can’t be fully outsourced, though: validating the firewall configuration stays the institution’s final responsibility no matter who else is involved. Anyone considering third-party help here should ask for specifics on exactly how that provider meets this regulatory requirement and keeps the network secure. A good provider saves real time while keeping an institution’s firewall current and efficient against today’s threats, and keeps every compliance and regulatory requirement met along the way.