service availability

Threema experienced significant disruptions due to large-scale DDoS attacks, rendering the service inaccessible for several hours on Tuesday and causing intermittent outages on Wednesday morning. The attacks targeted both Threema and its Swiss colocation partner, Nine, with service being unavailable from 7:30 p.m. to 11:30 p.m. CEST on Tuesday. By 12:23 p.m. on Wednesday, normal operations were restored. The security of Threema's systems and user data remained intact despite the service availability issues. The nature of the attacks made mitigation challenging, as attackers modified their methods rapidly. Threema's status page faced issues during the outage, and communication was conducted via email and social media. In response, Threema is implementing specialized upstream DDoS protection and plans to enhance its status page to provide monitoring for future disruptions.