On Saturday 3 May 2025 at 05:27 UTC, a WebSocket connection flood targeted a news publisher customer in the Nordics. The attack peaked at 792.5 million requests per second and lasted 104 minutes. Traffic originated from 1655 autonomous systems in 51 countries, predominantly a headless-browser farm.
| Vector | WebSocket connection flood |
| Peak | 792.5 million requests per second |
| Duration | 104 min |
| Time to mitigation | 0.865 s |
| Attack traffic reaching origin | 0.086% |
| Legitimate traffic challenged | 0.73% |
Timeline
The attack was preceded by a breaking political story. Request rates on the targeted routes exceeded their hourly baseline by a factor of 715 within 34 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
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Add a dedicated rate limit for the targeted route.
- Enable authenticated origin pulls.
- Review allow-listed partner ranges quarterly.