On Thursday 12 June 2025 at 12:35 UTC, a TLS handshake exhaustion targeted a sports betting customer in Western Europe. The attack peaked at 449.9 million requests per second and lasted 83 minutes. Traffic originated from 147 autonomous systems in 107 countries, predominantly a Mirai-derived IoT botnet.
| Vector | TLS handshake exhaustion |
| Peak | 449.9 million requests per second |
| Duration | 83 min |
| Time to mitigation | 0.785 s |
| Attack traffic reaching origin | 0.042% |
| Legitimate traffic challenged | 0.55% |
Timeline
The attack was preceded by a ransom note demanding payment in Monero. Request rates on the targeted routes exceeded their hourly baseline by a factor of 650 within 36 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
No customer-visible impact. The on-call engineer was notified and acknowledged the incident from the dashboard.
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.