On Tuesday 14 January 2025 at 04:45 UTC, a Slowloris targeted a online payments customer in the Benelux. The attack peaked at 844.1 million requests per second and lasted 141 minutes. Traffic originated from 1695 autonomous systems in 98 countries, predominantly mobile carrier ranges.
| Vector | Slowloris |
| Peak | 844.1 million requests per second |
| Duration | 141 min |
| Time to mitigation | 0.018 s |
| Attack traffic reaching origin | 0.079% |
| Legitimate traffic challenged | 0.64% |
Timeline
The attack was preceded by a ransom note demanding payment in Monero. Request rates on the targeted routes exceeded their hourly baseline by a factor of 540 within 19 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 217 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.
- Add a dedicated rate limit for the targeted route.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Clear and practical, thanks.
Clear and practical, thanks.
Is the risk score exposed in the logs so we can build our own dashboards on it?