On Sunday 16 June 2024 at 05:53 UTC, a UDP reflection (NTP) targeted a retail banking customer in Southeast Asia. The attack peaked at 343.2 Gbps and lasted 73 minutes. Traffic originated from 3154 autonomous systems in 40 countries, predominantly mobile carrier ranges.
| Vector | UDP reflection (NTP) |
| Peak | 343.2 Gbps |
| Duration | 73 min |
| Time to mitigation | 0.390 s |
| Attack traffic reaching origin | 0.004% |
| Legitimate traffic challenged | 0.78% |
Timeline
The attack was preceded by a ransom note demanding payment in Monero. 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
- 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.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Machine-readable ranges are at /ips.json and via the API.
Any plans to support per-tenant limits keyed on a JWT claim?
Is the risk score exposed in the logs so we can build our own dashboards on it?
Verified good bots and allow-listed partners bypass challenges entirely.
Thanks — sharing this with our on-call team.