DoS
Denial of Service
Überlastungs- bzw. Verfügbarkeitsangriff
A DoS attack aims to make a service or system unavailable for legitimate users — through overload or the targeted exploitation of a vulnerability that crashes the system. It attacks availability, one of the three protection goals of information security. The distributed variant with many sources is called DDoS.
History & facts. DoS differs fundamentally from attacks on confidentiality: it is not about stealing but about paralysing. This can happen via sheer load or via a targeted „hit“ — a single, cleverly formed request that triggers an error and crashes the service. Precisely in OT environments, where availability has top priority, an outage can directly endanger physical processes.
Outlook & recommendation. While the distributed variant (DDoS) requires above all filtering and absorption capacity, the vulnerability-based DoS can be prevented through patching and robust input validation. For critical services, redundancy, load limits and a rehearsed restart count. Since an availability outage at regulated entities can be reportable, DoS belongs in incident planning — not only as an IT but as a business risk.