On Tuesday 12 September 2023 at 02:52 UTC, a Slowloris targeted a fashion retail customer in the UK. The attack peaked at 925.1 million requests per second and lasted 38 minutes. Traffic originated from 2520 autonomous systems in 67 countries, predominantly misconfigured open reflectors.
| Vector | Slowloris |
| Peak | 925.1 million requests per second |
| Duration | 38 min |
| Time to mitigation | 0.298 s |
| Attack traffic reaching origin | 0.058% |
| Legitimate traffic challenged | 0.78% |
Timeline
The attack was preceded by a breaking political story. Request rates on the targeted routes exceeded their hourly baseline by a factor of 364 within 13 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 authenticated origin pulls.
- Review allow-listed partner ranges quarterly.
- Keep origin IPs out of public DNS history.