On Monday 30 October 2023 at 22:55 UTC, a login endpoint flood targeted a healthcare portal customer in Central Europe. The attack peaked at 283.4 million requests per second and lasted 5 minutes. Traffic originated from 722 autonomous systems in 9 countries, predominantly a headless-browser farm.
| Vector | login endpoint flood |
| Peak | 283.4 million requests per second |
| Duration | 5 min |
| Time to mitigation | 0.208 s |
| Attack traffic reaching origin | 0.086% |
| Legitimate traffic challenged | 0.36% |
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 581 within 11 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
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Review allow-listed partner ranges quarterly.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable authenticated origin pulls.