On Sunday 3 March 2024 at 01:28 UTC, a ACK flood targeted a tax authority portal customer in Central Europe. The attack peaked at 231.9 Gbps and lasted 130 minutes. Traffic originated from 4137 autonomous systems in 44 countries, predominantly a Mirai-derived IoT botnet.
| Vector | ACK flood |
| Peak | 231.9 Gbps |
| Duration | 130 min |
| Time to mitigation | 0.947 s |
| Attack traffic reaching origin | 0.003% |
| Legitimate traffic challenged | 0.10% |
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 15 points of presence.
What the customer saw
No customer-visible impact. The on-call engineer was notified and acknowledged the incident from the dashboard.
Recommendations
- Enable log streaming to your SIEM for faster correlation.
- Enable authenticated origin pulls.
- Lower challenge thresholds on authentication endpoints during high-risk events.
The point about origin IPs leaking through certificate transparency logs is underrated.
Good question. We will cover that in a follow-up post.
Is the risk score exposed in the logs so we can build our own dashboards on it?
Clear and practical, thanks.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.
Machine-readable ranges are at /ips.json and via the API.
The billing model is what got our finance team on board, honestly.
We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.
Interesting that most attacks are under ten minutes. Our experience is similar.
Interesting that most attacks are under ten minutes. Our experience is similar.
Solid runbook advice. The DNS-at-2am point hit home.
Thanks! Yes — the risk score and its components are included in every log record.