On Wednesday 19 October 2022 at 12:31 UTC, a UDP reflection (DNS) targeted a tax authority portal customer in the Nordics. The attack peaked at 238.3 Gbps and lasted 164 minutes. Traffic originated from 2345 autonomous systems in 43 countries, predominantly compromised cloud VMs.
| Vector | UDP reflection (DNS) |
| Peak | 238.3 Gbps |
| Duration | 164 min |
| Time to mitigation | 0.578 s |
| Attack traffic reaching origin | 0.069% |
| Legitimate traffic challenged | 0.68% |
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 18 points of presence.
What the customer saw
No customer-visible impact. The on-call engineer was notified and acknowledged the incident from the dashboard.
Recommendations
- Add a dedicated rate limit for the targeted route.
- Review allow-listed partner ranges quarterly.
- Enable authenticated origin pulls.
The point about origin IPs leaking through certificate transparency logs is underrated.
Do you publish the edge IP ranges in a machine-readable format?
Good question. We will cover that in a follow-up post.
The billing model is what got our finance team on board, honestly.
The point about origin IPs leaking through certificate transparency logs is underrated.
Could you share the dataset behind the percentages?