The CISA Alert: Security Beyond Solitary Confinement ---- - 20 minutes ago | 4 points | 0 comments - URL: https://jnior.com/blog/the-cisa-alert-security-beyond-solitary-confinement/ - Discussions: https://news.ycombinator.com/item?id=49956416 - Summary: The blog post discusses CISA's urgent warning about Internet-exposed operational technology (OT) and the need for stronger security. While acknowledging the importance of authentication and network protections, the author argues that requiring more processing power for cryptography can burden OT controllers, which must maintain deterministic operation. The post highlights that most Internet threats are automated scanners, not targeted attacks like Stuxnet. It introduces SYN greylisting, a technique implemented in JANOS (the JNIOR's operating system) that deliberately ignores initial TCP SYN packets, forcing scanners to retry while legitimate clients (which retransmit by design) still connect. This lightweight defense reduces resource consumption and preserves determinism without extra hardware. Tests on a public IP showed that disabling greylisting led to SSH attacks consuming 95% of processor time and even causing a watchdog reset. The author advocates for broader adoption of such low-cost defenses in embedded TCP/IP stacks, shifting the burden back to attackers and broadening the cybersecurity conversation beyond stronger cryptography.