On Sunday 5 December 2021 at 02:44 UTC, a UDP reflection (NTP) targeted a fashion retail customer in Southeast Asia. The attack peaked at 307.7 Gbps and lasted 52 minutes. Traffic originated from 2988 autonomous systems in 60 countries, predominantly mobile carrier ranges.
| Vector | UDP reflection (NTP) |
| Peak | 307.7 Gbps |
| Duration | 52 min |
| Time to mitigation | 0.096 s |
| Attack traffic reaching origin | 0.090% |
| Legitimate traffic challenged | 0.60% |
Timeline
The attack was preceded by a hacktivist channel announcing the target. 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 76 ms during the first minute, then normal service.
Recommendations
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Review allow-listed partner ranges quarterly.
- Keep origin IPs out of public DNS history.
Solid runbook advice. The DNS-at-2am point hit home.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Great to hear, thanks for sharing your experience.
Any plans to support per-tenant limits keyed on a JWT claim?
The point about origin IPs leaking through certificate transparency logs is underrated.
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.
Great write-up. We saw almost the same pattern on our login endpoint last month.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.