On Sunday 26 December 2021 at 07:05 UTC, a GRE flood targeted a healthcare portal customer in Iberia. The attack peaked at 367.9 Gbps and lasted 81 minutes. Traffic originated from 789 autonomous systems in 37 countries, predominantly a Mirai-derived IoT botnet.
| Vector | GRE flood |
| Peak | 367.9 Gbps |
| Duration | 81 min |
| Time to mitigation | 0.587 s |
| Attack traffic reaching origin | 0.041% |
| Legitimate traffic challenged | 0.45% |
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 36 points of presence.
What the customer saw
A brief increase in p99 latency of 33 ms during the first minute, then normal service.
Recommendations
- Review allow-listed partner ranges quarterly.
- Keep origin IPs out of public DNS history.
- Add a dedicated rate limit for the targeted route.
Great write-up. We saw almost the same pattern on our login endpoint last month.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.
Any plans to support per-tenant limits keyed on a JWT claim?
Carpet bombing is nasty. Good to see a clear explanation of it.
Do you publish the edge IP ranges in a machine-readable format?
Verified good bots and allow-listed partners bypass challenges entirely.
The billing model is what got our finance team on board, honestly.
Thanks — sharing this with our on-call team.