On Wednesday 13 November 2024 at 06:15 UTC, a TLS handshake exhaustion targeted a retail banking customer in Western Europe. The attack peaked at 597.8 million requests per second and lasted 16 minutes. Traffic originated from 258 autonomous systems in 24 countries, predominantly mobile carrier ranges.
| Vector | TLS handshake exhaustion |
| Peak | 597.8 million requests per second |
| Duration | 16 min |
| Time to mitigation | 0.314 s |
| Attack traffic reaching origin | 0.007% |
| Legitimate traffic challenged | 0.64% |
Timeline
The attack was preceded by no stated motive. Request rates on the targeted routes exceeded their hourly baseline by a factor of 845 within 25 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
- Add a dedicated rate limit for the targeted route.
- Review allow-listed partner ranges quarterly.
- Enable authenticated origin pulls.
The point about origin IPs leaking through certificate transparency logs is underrated.
Nice to read a vendor blog that admits what went wrong.
Good question. We will cover that in a follow-up post.
Carpet bombing is nasty. Good to see a clear explanation of it.
Carpet bombing is nasty. Good to see a clear explanation of it.
This matches what we see in iGaming around big matches.