On Tuesday 8 February 2022 at 22:31 UTC, a TLS handshake exhaustion targeted a electronics retail customer in Central Europe. The attack peaked at 813.8 million requests per second and lasted 136 minutes. Traffic originated from 1588 autonomous systems in 21 countries, predominantly a rented booter service.
| Vector | TLS handshake exhaustion |
| Peak | 813.8 million requests per second |
| Duration | 136 min |
| Time to mitigation | 0.271 s |
| Attack traffic reaching origin | 0.010% |
| Legitimate traffic challenged | 0.19% |
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 223 within 12 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
- Add a dedicated rate limit for the targeted route.
- Keep origin IPs out of public DNS history.
- Lower challenge thresholds on authentication endpoints during high-risk events.
Do you publish the edge IP ranges in a machine-readable format?
Our auditors asked for exactly this kind of incident evidence under DORA.
Interesting that most attacks are under ten minutes. Our experience is similar.
Interesting that most attacks are under ten minutes. Our experience is similar.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Thanks — sharing this with our on-call team.
Clear and practical, thanks.
Thanks — sharing this with our on-call team.
Great to hear, thanks for sharing your experience.