On Sunday 2 April 2023 at 07:35 UTC, a cache-busting query flood targeted a airline booking customer in Iberia. The attack peaked at 8.3 million requests per second and lasted 90 minutes. Traffic originated from 1618 autonomous systems in 107 countries, predominantly a rented booter service.
| Vector | cache-busting query flood |
| Peak | 8.3 million requests per second |
| Duration | 90 min |
| Time to mitigation | 0.278 s |
| Attack traffic reaching origin | 0.025% |
| Legitimate traffic challenged | 0.36% |
Timeline
The attack was preceded by no stated motive. Request rates on the targeted routes exceeded their hourly baseline by a factor of 92 within 39 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
- Keep origin IPs out of public DNS history.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable log streaming to your SIEM for faster correlation.
We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.
The point about origin IPs leaking through certificate transparency logs is underrated.