On Wednesday 8 March 2023 at 04:18 UTC, a UDP reflection (DNS) targeted a healthcare portal customer in the UK. The attack peaked at 109.8 Gbps and lasted 180 minutes. Traffic originated from 3377 autonomous systems in 117 countries, predominantly hijacked home routers.
| Vector | UDP reflection (DNS) |
| Peak | 109.8 Gbps |
| Duration | 180 min |
| Time to mitigation | 0.326 s |
| Attack traffic reaching origin | 0.018% |
| Legitimate traffic challenged | 0.40% |
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 27 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.
- Add a dedicated rate limit for the targeted route.
- Enable log streaming to your SIEM for faster correlation.
Solid runbook advice. The DNS-at-2am point hit home.
Is the risk score exposed in the logs so we can build our own dashboards on it?
Interesting that most attacks are under ten minutes. Our experience is similar.
Is the risk score exposed in the logs so we can build our own dashboards on it?