On Monday 12 February 2024 at 14:10 UTC, a Slowloris targeted a municipal services customer in the Benelux. The attack peaked at 891.2 million requests per second and lasted 114 minutes. Traffic originated from 449 autonomous systems in 21 countries, predominantly a Mirai-derived IoT botnet.
| Vector | Slowloris |
| Peak | 891.2 million requests per second |
| Duration | 114 min |
| Time to mitigation | 0.671 s |
| Attack traffic reaching origin | 0.001% |
| Legitimate traffic challenged | 0.35% |
Timeline
The attack was preceded by a hacktivist channel announcing the target. Request rates on the targeted routes exceeded their hourly baseline by a factor of 225 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
The customer’s status page stayed green throughout; they learned about the attack from our notification.
Recommendations
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable authenticated origin pulls.
- Review allow-listed partner ranges quarterly.