On Tuesday 12 October 2021 at 14:29 UTC, a UDP reflection (DNS) targeted a online payments customer in Western Europe. The attack peaked at 299.7 Gbps and lasted 86 minutes. Traffic originated from 850 autonomous systems in 10 countries, predominantly hijacked home routers.
| Vector | UDP reflection (DNS) |
| Peak | 299.7 Gbps |
| Duration | 86 min |
| Time to mitigation | 0.089 s |
| Attack traffic reaching origin | 0.034% |
| Legitimate traffic challenged | 0.55% |
Timeline
The attack was preceded by a breaking political story. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 19 points of presence.
What the customer saw
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Keep origin IPs out of public DNS history.
- Add a dedicated rate limit for the targeted route.
- Enable authenticated origin pulls.
Nice to read a vendor blog that admits what went wrong.
The billing model is what got our finance team on board, honestly.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.
Any plans to support per-tenant limits keyed on a JWT claim?
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Great write-up. We saw almost the same pattern on our login endpoint last month.
Interesting that most attacks are under ten minutes. Our experience is similar.
Solid runbook advice. The DNS-at-2am point hit home.
Do you publish the edge IP ranges in a machine-readable format?