On Friday 8 December 2023 at 01:41 UTC, a HTTP/2 rapid reset targeted a video streaming customer in the Benelux. The attack peaked at 236.5 million requests per second and lasted 101 minutes. Traffic originated from 945 autonomous systems in 77 countries, predominantly a headless-browser farm.
| Vector | HTTP/2 rapid reset |
| Peak | 236.5 million requests per second |
| Duration | 101 min |
| Time to mitigation | 0.548 s |
| Attack traffic reaching origin | 0.014% |
| Legitimate traffic challenged | 0.78% |
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 295 within 28 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
- Enable log streaming to your SIEM for faster correlation.
- Enable authenticated origin pulls.
- Keep origin IPs out of public DNS history.