On Tuesday 21 September 2021 at 21:32 UTC, a HTTP GET flood targeted a online payments customer in Central Europe. The attack peaked at 455.2 million requests per second and lasted 175 minutes. Traffic originated from 501 autonomous systems in 102 countries, predominantly a rented booter service.
| Vector | HTTP GET flood |
| Peak | 455.2 million requests per second |
| Duration | 175 min |
| Time to mitigation | 0.896 s |
| Attack traffic reaching origin | 0.040% |
| Legitimate traffic challenged | 0.76% |
Timeline
The attack was preceded by a publicly announced sales event. Request rates on the targeted routes exceeded their hourly baseline by a factor of 823 within 39 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.
- Add a dedicated rate limit for the targeted route.
- Enable authenticated origin pulls.