In my 30 years of infrastructure work, I’ve found them in almost every data center: The Zombie Servers.

These are the systems running in the corner that “nobody wants to touch.” The documentation is gone, the original admin retired a decade ago, and it’s running an OS that hasn’t seen a security patch in years.

But it’s still plugged in. And it’s still on the network. Heck, it might even be sealed behind a wall! (Bonus points if you get that reference without googling it.)

The 2026 Reality: In an AI-driven threat landscape, these aren’t just “old computers.” They are open doors. Modern automated scanners find these unpatched “zombies” in milliseconds and use them as a beachhead for lateral movement.

How to handle the Zombies:

✅ Audit with Intent: If a system hasn’t been active in 90 days, it’s a candidate for decommissioning.

✅ The “Scream Test”: Sometimes you have to turn it off and see who screams. (Metaphorically speaking… mostly).

✅ Isolate what you can’t kill: If a legacy system is business-critical, put it in strict isolation where it can’t infect the rest of your modern stack.

We often talk about “Innovation,” but true security leadership is often about the Decommission. You need to have the persistence to shut down the past to protect the future.

❓ What’s the oldest “Zombie” you’ve discovered lurking on a network? ❓