On Friday 19 June 2026 at 18:57 UTC, a WebSocket connection flood targeted a online casino customer in the UK. The attack peaked at 322.9 million requests per second and lasted 117 minutes. Traffic originated from 1474 autonomous systems in 86 countries, predominantly misconfigured open reflectors.
| Vector | WebSocket connection flood |
| Peak | 322.9 million requests per second |
| Duration | 117 min |
| Time to mitigation | 0.246 s |
| Attack traffic reaching origin | 0.062% |
| Legitimate traffic challenged | 0.27% |
Timeline
The attack was preceded by a competitor’s product launch. Request rates on the targeted routes exceeded their hourly baseline by a factor of 183 within 26 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
A brief increase in p99 latency of 79 ms during the first minute, then normal service.
Recommendations
- Review allow-listed partner ranges quarterly.
- Enable log streaming to your SIEM for faster correlation.
- Add a dedicated rate limit for the targeted route.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.
Solid runbook advice. The DNS-at-2am point hit home.
Do you publish the edge IP ranges in a machine-readable format?
The point about origin IPs leaking through certificate transparency logs is underrated.
Great to hear, thanks for sharing your experience.
Our auditors asked for exactly this kind of incident evidence under DORA.
Interesting that most attacks are under ten minutes. Our experience is similar.
Any plans to support per-tenant limits keyed on a JWT claim?