On Sunday 17 October 2021 at 21:43 UTC, a carpet-bombing UDP flood targeted a retail banking customer in Southeast Asia. The attack peaked at 168.0 Gbps and lasted 126 minutes. Traffic originated from 3787 autonomous systems in 104 countries, predominantly a headless-browser farm.
| Vector | carpet-bombing UDP flood |
| Peak | 168.0 Gbps |
| Duration | 126 min |
| Time to mitigation | 0.326 s |
| Attack traffic reaching origin | 0.084% |
| Legitimate traffic challenged | 0.75% |
Timeline
The attack was preceded by an extortion email received two days earlier. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 28 points of presence.
What the customer saw
A brief increase in p99 latency of 165 ms during the first minute, then normal service.
Recommendations
- Enable log streaming to your SIEM for faster correlation.
- Add a dedicated rate limit for the targeted route.
- Lower challenge thresholds on authentication endpoints during high-risk events.
The point about origin IPs leaking through certificate transparency logs is underrated.
Verified good bots and allow-listed partners bypass challenges entirely.
The billing model is what got our finance team on board, honestly.