On Tuesday 2 November 2021 at 11:17 UTC, a cache-busting query flood targeted a retail banking customer in Southeast Asia. The attack peaked at 153.6 million requests per second and lasted 55 minutes. Traffic originated from 3646 autonomous systems in 37 countries, predominantly a rented booter service.
| Vector | cache-busting query flood |
| Peak | 153.6 million requests per second |
| Duration | 55 min |
| Time to mitigation | 0.764 s |
| Attack traffic reaching origin | 0.007% |
| Legitimate traffic challenged | 0.62% |
Timeline
The attack was preceded by a competitor’s product launch. Request rates on the targeted routes exceeded their hourly baseline by a factor of 603 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
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Review allow-listed partner ranges quarterly.
- Keep origin IPs out of public DNS history.
- Lower challenge thresholds on authentication endpoints during high-risk events.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.
The billing model is what got our finance team on board, honestly.
The billing model is what got our finance team on board, honestly.
Thanks — sharing this with our on-call team.
This matches what we see in iGaming around big matches.
Great to hear, thanks for sharing your experience.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Interesting that most attacks are under ten minutes. Our experience is similar.