On Wednesday 26 November 2025 at 12:37 UTC, a Slowloris targeted a developer platform customer in the Benelux. The attack peaked at 630.4 million requests per second and lasted 121 minutes. Traffic originated from 3707 autonomous systems in 61 countries, predominantly misconfigured open reflectors.
| Vector | Slowloris |
| Peak | 630.4 million requests per second |
| Duration | 121 min |
| Time to mitigation | 0.082 s |
| Attack traffic reaching origin | 0.062% |
| Legitimate traffic challenged | 0.23% |
Timeline
The attack was preceded by an extortion email received two days earlier. Request rates on the targeted routes exceeded their hourly baseline by a factor of 874 within 5 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
A brief increase in p99 latency of 176 ms during the first minute, then normal service.
Recommendations
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Keep origin IPs out of public DNS history.
- Enable log streaming to your SIEM for faster correlation.
Interesting that most attacks are under ten minutes. Our experience is similar.