On Wednesday 10 July 2024 at 18:47 UTC, a cache-busting query flood targeted a healthcare portal customer in Western Europe. The attack peaked at 328.9 million requests per second and lasted 105 minutes. Traffic originated from 3350 autonomous systems in 70 countries, predominantly residential proxy networks.
| Vector | cache-busting query flood |
| Peak | 328.9 million requests per second |
| Duration | 105 min |
| Time to mitigation | 0.832 s |
| Attack traffic reaching origin | 0.035% |
| Legitimate traffic challenged | 0.77% |
Timeline
The attack was preceded by a ransom note demanding payment in Monero. Request rates on the targeted routes exceeded their hourly baseline by a factor of 245 within 40 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.
- Enable authenticated origin pulls.
Our auditors asked for exactly this kind of incident evidence under DORA.