On Saturday 12 August 2023 at 06:29 UTC, a HTTP POST flood targeted a crypto exchange customer in Western Europe. The attack peaked at 776.9 million requests per second and lasted 27 minutes. Traffic originated from 1518 autonomous systems in 8 countries, predominantly compromised cloud VMs.
| Vector | HTTP POST flood |
| Peak | 776.9 million requests per second |
| Duration | 27 min |
| Time to mitigation | 0.237 s |
| Attack traffic reaching origin | 0.070% |
| Legitimate traffic challenged | 0.41% |
Timeline
The attack was preceded by a hacktivist channel announcing the target. Request rates on the targeted routes exceeded their hourly baseline by a factor of 317 within 6 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 21 ms during the first minute, then normal service.
Recommendations
- Add a dedicated rate limit for the targeted route.
- Enable authenticated origin pulls.
- Keep origin IPs out of public DNS history.