On Thursday 5 August 2021 at 10:55 UTC, a Slowloris targeted a gaming community customer in the Nordics. The attack peaked at 357.2 million requests per second and lasted 145 minutes. Traffic originated from 148 autonomous systems in 93 countries, predominantly a rented booter service.
| Vector | Slowloris |
| Peak | 357.2 million requests per second |
| Duration | 145 min |
| Time to mitigation | 0.522 s |
| Attack traffic reaching origin | 0.079% |
| Legitimate traffic challenged | 0.74% |
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 595 within 22 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 223 ms during the first minute, then normal service.
Recommendations
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Add a dedicated rate limit for the targeted route.
- Keep origin IPs out of public DNS history.