The follow-up question from our Palo Alto piece was simple: if firewall patching is now non-negotiable, what happens when the device that gets popped isn’t a firewall but a VPN appliance sitting in front of a hospital network, and the attacker doesn’t need one flaw but three chained together to get root shell (full administrative control of the machine, no restrictions)? Here’s that argument played out.
The Skeptic: Let’s start with why this is different from a generic “patch your stuff” story. Three zero-days chained together means the vendor’s layered defenses failed in sequence, not just once. That’s not bad luck, that’s a design that assumed no one would ever get past the first wall.
The Optimist: Sure, but chaining three zero-days is also hard. That’s not some script kiddie with a scanner, that’s a well-resourced actor. Doesn’t that narrow who we should actually be worried about?
The Skeptic: It narrows who finds it first, not who uses it eventually. Once the chain is public or gets reverse-engineered from a patch, the skill requirement collapses. Healthcare IT teams don’t get to assume they’re only facing nation-state-level patience forever.
The Optimist: Okay, so what does that actually mean day to day for a hospital’s security team? Walk me through it.
The Skeptic: It means the VPN appliance, which is supposed to be the locked front door, is now a skeleton key to everything behind it. Root shell on the appliance often means the attacker can see credentials passing through, pivot into internal systems, and sit there quietly because these edge devices rarely get the same monitoring as laptops or servers inside the network.
The Optimist: Right, but that “sit there quietly” part cuts both ways. If detection is the weak link, the fix isn’t just patching faster, it’s actually watching these devices like we watch everything else. That’s a solvable gap, not a doomsday scenario.
The Skeptic: Solvable in theory. Here’s the catch for healthcare specifically: a lot of these VPN appliances connect to systems that can’t just be taken offline to patch. You’ve got remote clinicians, insurance verification systems, sometimes even connections tied to medical devices. Downtime has a cost that isn’t just inconvenience, it’s delayed care.
So what happens in practice is the patch sits in a queue behind a change-control process built for a world where nothing is actively being exploited.
The Optimist: So the real problem isn’t the vulnerability, it’s the gap between when a patch exists and when it’s safe to apply it in an environment that can’t tolerate downtime. That’s actually useful, because it points to a fix: segment the network so the VPN appliance isn’t a straight line into patient systems in the first place.
The Skeptic: Segmentation (basically building internal walls so a breach in one area doesn’t automatically reach another) helps, but most hospital networks were built over fifteen, twenty years through mergers, acquired clinics, and bolted-on vendor systems. Segmentation sounds clean in a diagram. In practice it’s chasing down three thousand point-of-care devices that the hospital doesn’t even have a full inventory of.
The Optimist: Fine, assume segmentation is years away for a lot of these systems. So what’s the actual cost if this specific Ivanti chain gets used against a hospital today, not hypothetically?
The Skeptic: Ransomware crews have already shown the playbook, get into the network, find the backup systems, encrypt what they can, and extort. In healthcare that’s meant ambulances diverted, surgeries postponed, lab results delayed. A root shell on the VPN appliance is just a faster, quieter way to get to that same endpoint. The 2024 Ascension incident showed what that cascade looks like even without a three-way zero-day chain involved.
The Optimist: That’s a real cost, I won’t argue with it. But escalate with me for a second: if the upside of fixing this properly is that hospitals finally get forced funding and attention for IT modernization that’s been ignored for a decade, is the scare worth it? Crises have moved budgets before.
The Skeptic: That’s a gamble with patient safety as the stake, not a strategy. Waiting for the disaster to justify the budget means someone’s care got disrupted first. And there’s no guarantee the money goes to the right fix, sometimes it goes to whatever vendor has the best sales pitch after the breach, not the boring unglamorous work of inventory and segmentation.
The Optimist: So what would you actually want to happen right now, concretely, instead of waiting?
The Skeptic: Treat every internet-facing VPN appliance as a standing liability, not a set-and-forget box. That means emergency patching authority that bypasses the normal change window when a chain like this is active, isolated monitoring on the appliance itself, and a real inventory of what’s actually reachable from it. None of that needs new technology, it needs institutional willingness to treat this as urgent before the breach, not after.
The Optimist: And I’d add that vendors need to be pushed to stop shipping this many layered flaws in the first place. Three zero-days chained together is partly a hospital IT problem, but it’s also Ivanti’s problem. If the pressure only lands on under-resourced hospital teams, we’re fixing the wrong end of this.
The Skeptic: On that, we agree.
What this exchange actually settles is that the danger isn’t the exploit chain’s sophistication, it’s where it lands: edge devices with weak visibility, sitting in front of networks that can’t easily tolerate downtime or rapid patching. What it doesn’t settle is who should bear the cost of fixing that mismatch, whether that’s hospitals with limited budgets, vendors shipping flawed appliances, or some forcing mechanism neither side has fully worked out yet.
This post is a follow-up responding to a discussion question raised in Palo Alto Networks’ PAN-OS Flaw Is a Reminder: Patching Firewalls Isn’t Optional Anymore: “Three Ivanti Zero-Days, One Root Shell: Why This VPN Bug Chain Should Worry Healthcare IT”