On Saturday 15 January 2022 at 12:53 UTC, a HTTP/2 rapid reset targeted a airline booking customer in Southeast Asia. The attack peaked at 369.3 million requests per second and lasted 76 minutes. Traffic originated from 3188 autonomous systems in 107 countries, predominantly residential proxy networks.
| Vector | HTTP/2 rapid reset |
| Peak | 369.3 million requests per second |
| Duration | 76 min |
| Time to mitigation | 0.916 s |
| Attack traffic reaching origin | 0.041% |
| Legitimate traffic challenged | 0.44% |
Timeline
The attack was preceded by an extortion email received two days earlier. Request rates on the targeted routes exceeded their hourly baseline by a factor of 685 within 35 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
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Add a dedicated rate limit for the targeted route.
- Enable log streaming to your SIEM for faster correlation.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Clear and practical, thanks.
Thanks! Yes — the risk score and its components are included in every log record.