On Wednesday 4 January 2023 at 08:41 UTC, a HTTP/2 rapid reset targeted a education platform customer in Western Europe. The attack peaked at 821.6 million requests per second and lasted 114 minutes. Traffic originated from 3318 autonomous systems in 51 countries, predominantly residential proxy networks.
| Vector | HTTP/2 rapid reset |
| Peak | 821.6 million requests per second |
| Duration | 114 min |
| Time to mitigation | 0.378 s |
| Attack traffic reaching origin | 0.088% |
| Legitimate traffic challenged | 0.69% |
Timeline
The attack was preceded by a ransom note demanding payment in Monero. Request rates on the targeted routes exceeded their hourly baseline by a factor of 134 within 23 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
- Add a dedicated rate limit for the targeted route.
- Enable log streaming to your SIEM for faster correlation.
- Keep origin IPs out of public DNS history.
We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.
Good question. We will cover that in a follow-up post.
Thanks — sharing this with our on-call team.
Clear and practical, thanks.