On Friday 1 November 2024 at 04:03 UTC, a UDP reflection (NTP) targeted a tax authority portal customer in Iberia. The attack peaked at 385.3 Gbps and lasted 50 minutes. Traffic originated from 3461 autonomous systems in 20 countries, predominantly mobile carrier ranges.
| Vector | UDP reflection (NTP) |
| Peak | 385.3 Gbps |
| Duration | 50 min |
| Time to mitigation | 0.074 s |
| Attack traffic reaching origin | 0.063% |
| Legitimate traffic challenged | 0.12% |
Timeline
The attack was preceded by no stated motive. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 39 points of presence.
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.
- Add a dedicated rate limit for the targeted route.
Nice to read a vendor blog that admits what went wrong.
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.
We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Clear and practical, thanks.
Good question. We will cover that in a follow-up post.