On Sunday 25 June 2023 at 16:00 UTC, a WebSocket connection flood targeted a sports betting customer in the Middle East. The attack peaked at 974.6 million requests per second and lasted 5 minutes. Traffic originated from 570 autonomous systems in 12 countries, predominantly a rented booter service.
| Vector | WebSocket connection flood |
| Peak | 974.6 million requests per second |
| Duration | 5 min |
| Time to mitigation | 0.708 s |
| Attack traffic reaching origin | 0.057% |
| Legitimate traffic challenged | 0.15% |
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 484 within 23 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
No customer-visible impact. The on-call engineer was notified and acknowledged the incident from the dashboard.
Recommendations
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable authenticated origin pulls.
- Review allow-listed partner ranges quarterly.
The point about origin IPs leaking through certificate transparency logs is underrated.
Our auditors asked for exactly this kind of incident evidence under DORA.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Great write-up. We saw almost the same pattern on our login endpoint last month.
Great to hear, thanks for sharing your experience.