On Saturday 5 June 2021 at 15:08 UTC, a WebSocket connection flood targeted a video streaming customer in Latin America. The attack peaked at 952.2 million requests per second and lasted 31 minutes. Traffic originated from 616 autonomous systems in 54 countries, predominantly compromised cloud VMs.
| Vector | WebSocket connection flood |
| Peak | 952.2 million requests per second |
| Duration | 31 min |
| Time to mitigation | 0.325 s |
| Attack traffic reaching origin | 0.003% |
| Legitimate traffic challenged | 0.78% |
Timeline
The attack was preceded by a competitor’s product launch. Request rates on the targeted routes exceeded their hourly baseline by a factor of 536 within 31 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 61 ms during the first minute, then normal service.
Recommendations
- Enable authenticated origin pulls.
- Review allow-listed partner ranges quarterly.
- Keep origin IPs out of public DNS history.