Microsoft Azure Fends Off ‘Largest DDoS Attack Ever Observed in the Cloud’

Microsoft confirmed that Azure blocked a denial-of-service attack that involved more than 500,000 IP addresses spread across multiple regions.

A tidal wave of internet traffic slammed into Microsoft Azure last month… and the company barely flinched.

Microsoft has confirmed that Azure blocked a 15.72 terabit-per-second (Tbps) distributed denial-of-service attack on Oct. 24, an assault so large that it set a new record for cloud-based DDoS incidents. The target was a single endpoint in Australia, but the traffic tsunami came from more than 500,000 IP addresses spread across multiple regions.

Sean Whalen, Azure Security senior product marketing manager, described the scale clearly in Microsoft’s blog post, writing: “On October 24, 2025, Azure DDOS Protection automatically detected and mitigated a multi-vector DDoS attack measuring 15.72 Tbps and nearly 3.64 billion packets per second (pps). This was the largest DDoS attack ...