On Saturday 1 February 2025 at 01:39 UTC, a HTTP/2 rapid reset targeted a electronics retail customer in Iberia. The attack peaked at 663.1 million requests per second and lasted 98 minutes. Traffic originated from 2484 autonomous systems in 86 countries, predominantly a Mirai-derived IoT botnet.
| Vector | HTTP/2 rapid reset |
| Peak | 663.1 million requests per second |
| Duration | 98 min |
| Time to mitigation | 0.725 s |
| Attack traffic reaching origin | 0.045% |
| Legitimate traffic challenged | 0.51% |
Timeline
The attack was preceded by a publicly announced sales event. Request rates on the targeted routes exceeded their hourly baseline by a factor of 726 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
No customer-visible impact. The on-call engineer was notified and acknowledged the incident from the dashboard.
Recommendations
- Enable authenticated origin pulls.
- Review allow-listed partner ranges quarterly.
- Lower challenge thresholds on authentication endpoints during high-risk events.
This matches what we see in iGaming around big matches.
Machine-readable ranges are at /ips.json and via the API.
Great write-up. We saw almost the same pattern on our login endpoint last month.
The point about origin IPs leaking through certificate transparency logs is underrated.
Thanks — sharing this with our on-call team.