On Saturday 6 June 2026 at 23:24 UTC, a TLS handshake exhaustion targeted a online casino customer in Western Europe. The attack peaked at 636.4 million requests per second and lasted 11 minutes. Traffic originated from 689 autonomous systems in 113 countries, predominantly mobile carrier ranges.
| Vector | TLS handshake exhaustion |
| Peak | 636.4 million requests per second |
| Duration | 11 min |
| Time to mitigation | 0.872 s |
| Attack traffic reaching origin | 0.081% |
| Legitimate traffic challenged | 0.01% |
Timeline
The attack was preceded by a hacktivist channel announcing the target. Request rates on the targeted routes exceeded their hourly baseline by a factor of 878 within 21 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 105 ms during the first minute, then normal service.
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.
Our auditors asked for exactly this kind of incident evidence under DORA.
Interesting that most attacks are under ten minutes. Our experience is similar.
Our auditors asked for exactly this kind of incident evidence under DORA.
We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.