On Thursday 18 May 2023 at 06:14 UTC, a HTTP POST flood targeted a crypto exchange customer in North America. The attack peaked at 442.3 million requests per second and lasted 84 minutes. Traffic originated from 2989 autonomous systems in 68 countries, predominantly a headless-browser farm.
| Vector | HTTP POST flood |
| Peak | 442.3 million requests per second |
| Duration | 84 min |
| Time to mitigation | 0.601 s |
| Attack traffic reaching origin | 0.074% |
| Legitimate traffic challenged | 0.67% |
Timeline
The attack was preceded by a breaking political story. Request rates on the targeted routes exceeded their hourly baseline by a factor of 118 within 15 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
The customer’s status page stayed green throughout; they learned about the attack from our notification.
Recommendations
- Keep origin IPs out of public DNS history.
- Review allow-listed partner ranges quarterly.
- Enable authenticated origin pulls.