{"id":7380,"date":"2025-01-08T09:00:00","date_gmt":"2025-01-08T09:00:00","guid":{"rendered":"https:\/\/www.securitytoday.de\/2026\/04\/02\/post_id-3693-2\/"},"modified":"2026-07-04T12:24:23","modified_gmt":"2026-07-04T12:24:23","slug":"case-study-how-an-energy-supplier-contained-a-ransomware-attack-in-4-hours","status":"publish","type":"post","link":"https:\/\/www.securitytoday.de\/en\/2025\/01\/08\/case-study-how-an-energy-supplier-contained-a-ransomware-attack-in-4-hours\/","title":{"rendered":"Case Study: How an Energy Supplier Contained a Ransomware Attack in 4 Hours"},"content":{"rendered":"

A regional energy supplier became the target of a ransomware attack. Thanks to prepared network segmentation and a tested incident response plan, the spread was stopped within 4 hours.<\/strong><\/p>\n

TL;DR<\/h2>\n

A regional energy supplier with 1,200 employees was targeted by a ransomware attack from the BlackCat\/ALPHV group in October 2024. Thanks to prepared network segmentation and a tested incident response plan, the spread was stopped within 4 hours. The KRITIS-relevant OT systems remained completely protected.<\/p>\n

Initial Situation<\/h2>\n

The company operates power and heating networks for a region with over 300,000 inhabitants. As a KRITIS operator, it is subject to strict security requirements. The IT environment comprises around 800 endpoints, 60 servers, and a separate OT network for control technology.<\/p>\n

The attack began via a compromised VPN connection of an external service provider. The attackers used stolen credentials to move laterally within the IT network.<\/p>\n

Detection and Response<\/h2>\n

Minute 0 (02:14 AM):<\/strong> The EDR system detects unusual PowerShell execution on a file server and automatically isolates the endpoint.<\/p>\n

Minute 15:<\/strong> The on-call service is automatically alerted via SMS. The IT manager activates the crisis team.<\/p>\n

Hour 1:<\/strong> Initial forensic analysis identifies the attack vector (compromised VPN account). All VPN connections of the service provider are terminated.<\/p>\n

Hours 2-3:<\/strong> Lateral movement on 3 additional servers is identified. All affected systems are isolated. The OT network is protected by an air gap and unaffected.<\/p>\n

Hour 4:<\/strong> Containment confirmed. No access to customer data or OT systems. BSI (Federal Office for Information Security) report is triggered.<\/p>\n

Success Factors<\/h2>\n