On Saturday 10 June 2023 at 02:29 UTC, a TLS handshake exhaustion targeted a retail banking customer in Latin America. The attack peaked at 803.6 million requests per second and lasted 76 minutes. Traffic originated from 668 autonomous systems in 19 countries, predominantly a Mirai-derived IoT botnet.
| Vector | TLS handshake exhaustion |
| Peak | 803.6 million requests per second |
| Duration | 76 min |
| Time to mitigation | 0.011 s |
| Attack traffic reaching origin | 0.003% |
| Legitimate traffic challenged | 0.56% |
Timeline
The attack was preceded by no stated motive. Request rates on the targeted routes exceeded their hourly baseline by a factor of 824 within 38 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.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable authenticated origin pulls.