On Thursday 25 May 2023 at 03:54 UTC, a ACK flood targeted a education platform customer in the Middle East. The attack peaked at 341.7 Gbps and lasted 150 minutes. Traffic originated from 3109 autonomous systems in 113 countries, predominantly compromised cloud VMs.
| Vector | ACK flood |
| Peak | 341.7 Gbps |
| Duration | 150 min |
| Time to mitigation | 0.864 s |
| Attack traffic reaching origin | 0.003% |
| Legitimate traffic challenged | 0.25% |
Timeline
The attack was preceded by no stated motive. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 34 points of presence.
What the customer saw
A brief increase in p99 latency of 68 ms during the first minute, then normal service.
Recommendations
- Review allow-listed partner ranges quarterly.
- Enable authenticated origin pulls.
- Keep origin IPs out of public DNS history.
Our auditors asked for exactly this kind of incident evidence under DORA.
Good question. We will cover that in a follow-up post.
This matches what we see in iGaming around big matches.
Great to hear, thanks for sharing your experience.
How do you avoid challenging uptime monitors and partners?
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.
Machine-readable ranges are at /ips.json and via the API.
Great write-up. We saw almost the same pattern on our login endpoint last month.