On Thursday 22 May 2025 at 20:39 UTC, a ACK flood targeted a sports betting customer in Iberia. The attack peaked at 91.0 Gbps and lasted 81 minutes. Traffic originated from 2934 autonomous systems in 39 countries, predominantly a Mirai-derived IoT botnet.
| Vector | ACK flood |
| Peak | 91.0 Gbps |
| Duration | 81 min |
| Time to mitigation | 0.904 s |
| Attack traffic reaching origin | 0.027% |
| Legitimate traffic challenged | 0.62% |
Timeline
The attack was preceded by an extortion email received two days earlier. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 22 points of presence.
What the customer saw
The customer’s status page stayed green throughout; they learned about the attack from our notification.
Recommendations
- Review allow-listed partner ranges quarterly.
- Add a dedicated rate limit for the targeted route.
- Lower challenge thresholds on authentication endpoints during high-risk events.
Do you publish the edge IP ranges in a machine-readable format?
How do you avoid challenging uptime monitors and partners?
Great to hear, thanks for sharing your experience.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Great write-up. We saw almost the same pattern on our login endpoint last month.
Great write-up. We saw almost the same pattern on our login endpoint last month.
Machine-readable ranges are at /ips.json and via the API.