On Sunday 15 September 2024 at 02:18 UTC, a Slowloris targeted a video streaming customer in Western Europe. The attack peaked at 828.5 million requests per second and lasted 128 minutes. Traffic originated from 3256 autonomous systems in 52 countries, predominantly misconfigured open reflectors.
| Vector | Slowloris |
| Peak | 828.5 million requests per second |
| Duration | 128 min |
| Time to mitigation | 0.670 s |
| Attack traffic reaching origin | 0.017% |
| Legitimate traffic challenged | 0.33% |
Timeline
The attack was preceded by a breaking political story. Request rates on the targeted routes exceeded their hourly baseline by a factor of 543 within 35 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
- Add a dedicated rate limit for the targeted route.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Keep origin IPs out of public DNS history.
Carpet bombing is nasty. Good to see a clear explanation of it.
We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.
The billing model is what got our finance team on board, honestly.
Thanks! Yes — the risk score and its components are included in every log record.