On Saturday 3 January 2026 at 02:24 UTC, a WebSocket connection flood targeted a healthcare portal customer in the UK. The attack peaked at 660.8 million requests per second and lasted 183 minutes. Traffic originated from 1865 autonomous systems in 59 countries, predominantly residential proxy networks.
| Vector | WebSocket connection flood |
| Peak | 660.8 million requests per second |
| Duration | 183 min |
| Time to mitigation | 0.872 s |
| Attack traffic reaching origin | 0.079% |
| Legitimate traffic challenged | 0.51% |
Timeline
The attack was preceded by no stated motive. Request rates on the targeted routes exceeded their hourly baseline by a factor of 514 within 16 seconds. The risk score of participating clients crossed the challenge threshold automatically and proof-of-work difficulty rose with origin load.
What the customer saw
The customer’s status page stayed green throughout; they learned about the attack from our notification.
Recommendations
- Add a dedicated rate limit for the targeted route.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable log streaming to your SIEM for faster correlation.