On Saturday 22 June 2024 at 15:04 UTC, a TLS handshake exhaustion targeted a crypto exchange customer in Latin America. The attack peaked at 225.9 million requests per second and lasted 133 minutes. Traffic originated from 2965 autonomous systems in 79 countries, predominantly a headless-browser farm.
| Vector | TLS handshake exhaustion |
| Peak | 225.9 million requests per second |
| Duration | 133 min |
| Time to mitigation | 0.235 s |
| Attack traffic reaching origin | 0.036% |
| Legitimate traffic challenged | 0.30% |
Timeline
The attack was preceded by an extortion email received two days earlier. Request rates on the targeted routes exceeded their hourly baseline by a factor of 683 within 32 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
- Keep origin IPs out of public DNS history.
- Enable authenticated origin pulls.
- Add a dedicated rate limit for the targeted route.