On Tuesday 11 July 2023 at 08:21 UTC, a UDP reflection (NTP) targeted a education platform customer in Western Europe. The attack peaked at 17.3 Gbps and lasted 73 minutes. Traffic originated from 693 autonomous systems in 32 countries, predominantly compromised cloud VMs.
| Vector | UDP reflection (NTP) |
| Peak | 17.3 Gbps |
| Duration | 73 min |
| Time to mitigation | 0.833 s |
| Attack traffic reaching origin | 0.028% |
| Legitimate traffic challenged | 0.57% |
Timeline
The attack was preceded by an extortion email received two days earlier. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 19 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.
- Keep origin IPs out of public DNS history.
- Enable authenticated origin pulls.
The point about origin IPs leaking through certificate transparency logs is underrated.