On Friday 11 November 2022 at 19:41 UTC, a credential stuffing targeted a education platform customer in Central Europe. The attack peaked at 496.9 million requests per second and lasted 161 minutes. Traffic originated from 3520 autonomous systems in 69 countries, predominantly compromised cloud VMs.
| Vector | credential stuffing |
| Peak | 496.9 million requests per second |
| Duration | 161 min |
| Time to mitigation | 0.254 s |
| Attack traffic reaching origin | 0.013% |
| Legitimate traffic challenged | 0.10% |
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 830 within 30 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 206 ms during the first minute, then normal service.
Recommendations
- Add a dedicated rate limit for the targeted route.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Keep origin IPs out of public DNS history.