On Saturday 3 August 2024 at 08:14 UTC, a Slowloris targeted a online payments customer in Western Europe. The attack peaked at 947.4 million requests per second and lasted 4 minutes. Traffic originated from 2645 autonomous systems in 13 countries, predominantly misconfigured open reflectors.
| Vector | Slowloris |
| Peak | 947.4 million requests per second |
| Duration | 4 min |
| Time to mitigation | 0.614 s |
| Attack traffic reaching origin | 0.081% |
| Legitimate traffic challenged | 0.33% |
Timeline
The attack was preceded by a publicly announced sales event. Request rates on the targeted routes exceeded their hourly baseline by a factor of 848 within 21 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
- Enable log streaming to your SIEM for faster correlation.
- Enable authenticated origin pulls.
- Lower challenge thresholds on authentication endpoints during high-risk events.
Is the risk score exposed in the logs so we can build our own dashboards on it?
Clear and practical, thanks.
We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.