On Monday 12 July 2021 at 16:53 UTC, a HTTP POST flood targeted a news publisher customer in North America. The attack peaked at 935.8 million requests per second and lasted 73 minutes. Traffic originated from 2388 autonomous systems in 25 countries, predominantly misconfigured open reflectors.
| Vector | HTTP POST flood |
| Peak | 935.8 million requests per second |
| Duration | 73 min |
| Time to mitigation | 0.430 s |
| Attack traffic reaching origin | 0.025% |
| Legitimate traffic challenged | 0.29% |
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 288 within 24 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 213 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 log streaming to your SIEM for faster correlation.