On Wednesday 24 March 2021 at 16:16 UTC, a UDP reflection (DNS) targeted a sports betting customer in the UK. The attack peaked at 350.2 Gbps and lasted 159 minutes. Traffic originated from 2470 autonomous systems in 104 countries, predominantly residential proxy networks.
| Vector | UDP reflection (DNS) |
| Peak | 350.2 Gbps |
| Duration | 159 min |
| Time to mitigation | 0.424 s |
| Attack traffic reaching origin | 0.088% |
| Legitimate traffic challenged | 0.67% |
Timeline
The attack was preceded by a hacktivist channel announcing the target. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 35 points of presence.
What the customer saw
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Add a dedicated rate limit for the targeted route.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Keep origin IPs out of public DNS history.