OT Cybersecurity Lessons Learned from the Frontlines

### Executive summary: The Dragos 2026 OT/ICS Cybersecurity Year in Review synthesizes frontline findings from incident response, assessments, penetration tests, tabletop exercises, and OT telemetry to highlight recurring operational and security gaps—notably poor IT/OT segmentation, limited visibility and monitoring, insecure remote access, and immature risk-based vulnerability management—that contributed to malware and ransomware incidents and extended outages in 2025.