On Monday 3 November 2025 at 18:03 UTC, a UDP reflection (NTP) targeted a online payments customer in Western Europe. The attack peaked at 237.5 Gbps and lasted 139 minutes. Traffic originated from 153 autonomous systems in 81 countries, predominantly a headless-browser farm.
| Vector | UDP reflection (NTP) |
| Peak | 237.5 Gbps |
| Duration | 139 min |
| Time to mitigation | 0.108 s |
| Attack traffic reaching origin | 0.076% |
| Legitimate traffic challenged | 0.43% |
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 16 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.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Keep origin IPs out of public DNS history.