On Friday 2 May 2025 at 02:11 UTC, a HTTP POST flood targeted a healthcare portal customer in the UK. The attack peaked at 581.9 million requests per second and lasted 36 minutes. Traffic originated from 2162 autonomous systems in 35 countries, predominantly hijacked home routers.
| Vector | HTTP POST flood |
| Peak | 581.9 million requests per second |
| Duration | 36 min |
| Time to mitigation | 0.680 s |
| Attack traffic reaching origin | 0.055% |
| Legitimate traffic challenged | 0.40% |
Timeline
The attack was preceded by a breaking political story. Request rates on the targeted routes exceeded their hourly baseline by a factor of 831 within 9 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
- Enable authenticated origin pulls.
- Enable log streaming to your SIEM for faster correlation.
- Lower challenge thresholds on authentication endpoints during high-risk events.