On Saturday 3 July 2021 at 09:31 UTC, a HTTP GET flood targeted a crypto exchange customer in Southeast Asia. The attack peaked at 369.5 million requests per second and lasted 63 minutes. Traffic originated from 629 autonomous systems in 27 countries, predominantly residential proxy networks.
| Vector | HTTP GET flood |
| Peak | 369.5 million requests per second |
| Duration | 63 min |
| Time to mitigation | 0.110 s |
| Attack traffic reaching origin | 0.079% |
| Legitimate traffic challenged | 0.17% |
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 881 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
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Enable authenticated origin pulls.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Review allow-listed partner ranges quarterly.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.