Annual Distributed Denial-of-Service Analysis 2025

This report presents an analysis of Distributed Denial-of-Service (DDoS) attacks detected and mitigated by DigiCert's UltraDDoS Protect service throughout 2025. The report outlines the significant decrease in overall DDoS attack volume, with a total of 29,998 attacks recorded, representing an 88.91% reduction compared to 2024. This decline is attributed to global law enforcement actions and internal adjustments made by DigiCert's Security Operations Center. The report details the emergence of tsunami-class DDoS attacks, which exceeded one terabit per second, highlighting a shift towards fewer but more impactful attacks. It also discusses the operational characteristics of these attacks, noting that most were simpler and shorter in duration, with a majority relying on single attack vectors. The report emphasizes the importance of maintaining robust defenses against both routine and high-capacity DDoS threats, particularly in targeted sectors such as Financial Services and IT/Technical Services.