Cyber Resilience Briefing — April 21, 2025
OT ransomware crews pivot to operational data stores; Zeph Tech delivers containment patterns mapped to NIST SP 800-82 and IEC 62443-3-3 SR 5.
Executive briefing: Ransomware groups continue to probe industrial environments by piggybacking on remote maintenance tools and targeting historians. Zeph Tech is distributing pre-built containment playbooks and golden images so OT teams can restore operations within agreed recovery point objectives.
Key industry signals
- OT ransomware trendlines. Dragos’ 2023 report noted a record number of ransomware incidents impacting industrial organisations, with access often gained through dual-use admin tooling.
- Guidance from StopRansomware.gov. CISA’s Stop Ransomware platform stresses network segmentation, offline backups, and tabletop exercises that account for safety-critical operations.
- Control framework expectations. The draft revision of NIST SP 800-82 reinforces asset inventory, zoning, and incident response coordination between IT and OT security teams.
Control alignment
- NIST SP 800-82. Validate network segmentation diagrams quarterly and align them with live asset inventories covering PLCs, HMIs, and historians.
- IEC 62443-3-3 SR 5. Demonstrate that remote sessions enforce strong authentication, least privilege, and monitoring before any changes touch control equipment.
Detection and response priorities
- Alert when OT jump hosts see credential reuse from IT networks or when remote tooling spawns encryption utilities.
- Flag unauthorised changes to PLC ladder logic, historian retention policies, or safety instrumented system configurations.
- Cross-check detection coverage against the critical infrastructure detection modernization briefing so OT alerts feed enterprise SOC workflows.
Enablement moves
- Update crisis communications templates to cover physical safety messaging alongside data privacy statements for regulators and partners.
- Stage spare components and tested system images at regional depots so maintenance crews can perform rapid swap-outs after containment.
Sources
- Dragos 2023 OT Cybersecurity Year in Review
- CISA Stop Ransomware resource hub
- NIST SP 800-82 Rev. 3 (Draft) Guide to Industrial Control Systems Security
Zeph Tech blends OT asset discovery, segmented monitoring, and incident rehearsal so industrial teams can sustain uptime despite ransomware pressure.