On Friday 2 April 2021 at 23:28 UTC, a UDP reflection (NTP) targeted a ticketing customer in Southeast Asia. The attack peaked at 185.8 Gbps and lasted 183 minutes. Traffic originated from 4092 autonomous systems in 35 countries, predominantly a headless-browser farm.
| Vector | UDP reflection (NTP) |
| Peak | 185.8 Gbps |
| Duration | 183 min |
| Time to mitigation | 0.840 s |
| Attack traffic reaching origin | 0.074% |
| Legitimate traffic challenged | 0.15% |
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 38 points of presence.
What the customer saw
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable log streaming to your SIEM for faster correlation.
- Add a dedicated rate limit for the targeted route.
Nice to read a vendor blog that admits what went wrong.
Do you publish the edge IP ranges in a machine-readable format?
Any plans to support per-tenant limits keyed on a JWT claim?
Carpet bombing is nasty. Good to see a clear explanation of it.
Nice to read a vendor blog that admits what went wrong.
Great write-up. We saw almost the same pattern on our login endpoint last month.
Solid runbook advice. The DNS-at-2am point hit home.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Do you publish the edge IP ranges in a machine-readable format?