On Saturday 31 May 2025 at 09:24 UTC, a login endpoint flood targeted a fashion retail customer in Iberia. The attack peaked at 396.7 million requests per second and lasted 26 minutes. Traffic originated from 1084 autonomous systems in 7 countries, predominantly misconfigured open reflectors.
| Vector | login endpoint flood |
| Peak | 396.7 million requests per second |
| Duration | 26 min |
| Time to mitigation | 0.030 s |
| Attack traffic reaching origin | 0.025% |
| Legitimate traffic challenged | 0.08% |
Timeline
The attack was preceded by a publicly announced sales event. Request rates on the targeted routes exceeded their hourly baseline by a factor of 235 within 34 seconds. The risk score of participating clients crossed the challenge threshold automatically and proof-of-work difficulty rose with origin load.
What the customer saw
A brief increase in p99 latency of 186 ms during the first minute, then normal service.
Recommendations
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable log streaming to your SIEM for faster correlation.
- Review allow-listed partner ranges quarterly.