On Saturday 27 September 2025 at 01:30 UTC, a UDP reflection (DNS) targeted a online payments customer in Iberia. The attack peaked at 316.0 Gbps and lasted 30 minutes. Traffic originated from 3203 autonomous systems in 42 countries, predominantly compromised cloud VMs.
| Vector | UDP reflection (DNS) |
| Peak | 316.0 Gbps |
| Duration | 30 min |
| Time to mitigation | 0.679 s |
| Attack traffic reaching origin | 0.055% |
| Legitimate traffic challenged | 0.41% |
Timeline
The attack was preceded by a publicly announced sales event. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 37 points of presence.
What the customer saw
A brief increase in p99 latency of 46 ms during the first minute, then normal service.
Recommendations
- Enable authenticated origin pulls.
- Enable log streaming to your SIEM for faster correlation.
- Review allow-listed partner ranges quarterly.
Is the risk score exposed in the logs so we can build our own dashboards on it?
The billing model is what got our finance team on board, honestly.
Do you publish the edge IP ranges in a machine-readable format?
Good question. We will cover that in a follow-up post.
Would love a follow-up on how you handle HTTP/3 fingerprinting.