On Tuesday 6 May 2025 at 01:58 UTC, a SYN flood targeted a sports betting customer in Central Europe. The attack peaked at 324.7 Gbps and lasted 16 minutes. Traffic originated from 1813 autonomous systems in 115 countries, predominantly a headless-browser farm.
| Vector | SYN flood |
| Peak | 324.7 Gbps |
| Duration | 16 min |
| Time to mitigation | 0.655 s |
| Attack traffic reaching origin | 0.053% |
| Legitimate traffic challenged | 0.32% |
Timeline
The attack was preceded by a ransom note demanding payment in Monero. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 24 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.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable log streaming to your SIEM for faster correlation.
Is the risk score exposed in the logs so we can build our own dashboards on it?
Clear and practical, thanks.
Good question. We will cover that in a follow-up post.