On Monday 13 November 2023 at 20:27 UTC, a HTTP GET flood targeted a healthcare portal customer in Iberia. The attack peaked at 91.7 million requests per second and lasted 41 minutes. Traffic originated from 1605 autonomous systems in 114 countries, predominantly residential proxy networks.
| Vector | HTTP GET flood |
| Peak | 91.7 million requests per second |
| Duration | 41 min |
| Time to mitigation | 0.063 s |
| Attack traffic reaching origin | 0.074% |
| Legitimate traffic challenged | 0.03% |
Timeline
The attack was preceded by a breaking political story. Request rates on the targeted routes exceeded their hourly baseline by a factor of 327 within 7 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
No customer-visible impact. The on-call engineer was notified and acknowledged the incident from the dashboard.
Recommendations
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Add a dedicated rate limit for the targeted route.
- Enable log streaming to your SIEM for faster correlation.
Clear and practical, thanks.