On Sunday 12 March 2023 at 05:20 UTC, a TLS handshake exhaustion targeted a news publisher customer in Iberia. The attack peaked at 978.8 million requests per second and lasted 83 minutes. Traffic originated from 1648 autonomous systems in 82 countries, predominantly mobile carrier ranges.
| Vector | TLS handshake exhaustion |
| Peak | 978.8 million requests per second |
| Duration | 83 min |
| Time to mitigation | 0.707 s |
| Attack traffic reaching origin | 0.026% |
| Legitimate traffic challenged | 0.77% |
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 308 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
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Review allow-listed partner ranges quarterly.
- Keep origin IPs out of public DNS history.
- Add a dedicated rate limit for the targeted route.
Is the risk score exposed in the logs so we can build our own dashboards on it?