On Tuesday 11 November 2025 at 23:42 UTC, a HTTP/2 rapid reset targeted a sports betting customer in Iberia. The attack peaked at 958.8 million requests per second and lasted 166 minutes. Traffic originated from 1976 autonomous systems in 25 countries, predominantly compromised cloud VMs.
| Vector | HTTP/2 rapid reset |
| Peak | 958.8 million requests per second |
| Duration | 166 min |
| Time to mitigation | 0.822 s |
| Attack traffic reaching origin | 0.043% |
| Legitimate traffic challenged | 0.27% |
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 388 within 13 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
The customer’s status page stayed green throughout; they learned about the attack from our notification.
Recommendations
- Keep origin IPs out of public DNS history.
- Enable authenticated origin pulls.
- Lower challenge thresholds on authentication endpoints during high-risk events.