CISA's Urgent OT Warning: Why the Best Defense May Be Invisibility

The CISA Alert: Security Beyond Solitary Confinement

CISA's urgent alert rightly warns that operational technology exposed to the public Internet is under relentless attack. But Bruce Cloutier argues that simply adding stronger authentication and cryptography can backfire, because attackers don't need to break in—they only need to make the controller do expensive work. He proposes a lightweight alternative already built into JANOS: SYN greylisting, which ignores the first connection attempt and forces scanners to retry, shifting the cost back to the attacker without new hardware or cloud services.