On Monday 20 May 2024 at 19:52 UTC, a TLS handshake exhaustion targeted a developer platform customer in North America. The attack peaked at 854.1 million requests per second and lasted 91 minutes. Traffic originated from 1573 autonomous systems in 83 countries, predominantly a Mirai-derived IoT botnet.
| Vector | TLS handshake exhaustion |
| Peak | 854.1 million requests per second |
| Duration | 91 min |
| Time to mitigation | 0.379 s |
| Attack traffic reaching origin | 0.075% |
| Legitimate traffic challenged | 0.35% |
Timeline
The attack was preceded by a publicly announced sales event. Request rates on the targeted routes exceeded their hourly baseline by a factor of 454 within 8 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
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Review allow-listed partner ranges quarterly.
- Add a dedicated rate limit for the targeted route.