On Thursday 22 September 2022 at 14:57 UTC, a UDP reflection (DNS) targeted a online payments customer in Western Europe. The attack peaked at 199.2 Gbps and lasted 109 minutes. Traffic originated from 3368 autonomous systems in 73 countries, predominantly misconfigured open reflectors.
| Vector | UDP reflection (DNS) |
| Peak | 199.2 Gbps |
| Duration | 109 min |
| Time to mitigation | 0.282 s |
| Attack traffic reaching origin | 0.013% |
| Legitimate traffic challenged | 0.24% |
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 25 points of presence.
What the customer saw
A brief increase in p99 latency of 71 ms during the first minute, then normal service.
Recommendations
- Add a dedicated rate limit for the targeted route.
- Keep origin IPs out of public DNS history.
- Enable log streaming to your SIEM for faster correlation.
Interesting that most attacks are under ten minutes. Our experience is similar.
Thanks! Yes — the risk score and its components are included in every log record.
Thanks — sharing this with our on-call team.
Is the risk score exposed in the logs so we can build our own dashboards on it?
The point about origin IPs leaking through certificate transparency logs is underrated.