On Thursday 3 August 2023 at 13:11 UTC, a HTTP/2 rapid reset targeted a education platform customer in Latin America. The attack peaked at 782.7 million requests per second and lasted 9 minutes. Traffic originated from 2015 autonomous systems in 63 countries, predominantly hijacked home routers.
| Vector | HTTP/2 rapid reset |
| Peak | 782.7 million requests per second |
| Duration | 9 min |
| Time to mitigation | 0.178 s |
| Attack traffic reaching origin | 0.007% |
| Legitimate traffic challenged | 0.67% |
Timeline
The attack was preceded by an extortion email received two days earlier. Request rates on the targeted routes exceeded their hourly baseline by a factor of 378 within 32 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 112 ms during the first minute, then normal service.
Recommendations
- Add a dedicated rate limit for the targeted route.
- Review allow-listed partner ranges quarterly.
- Enable authenticated origin pulls.