On Saturday 7 October 2023 at 19:41 UTC, a credential stuffing targeted a online payments customer in the Nordics. The attack peaked at 512.1 million requests per second and lasted 61 minutes. Traffic originated from 2951 autonomous systems in 109 countries, predominantly hijacked home routers.
| Vector | credential stuffing |
| Peak | 512.1 million requests per second |
| Duration | 61 min |
| Time to mitigation | 0.484 s |
| Attack traffic reaching origin | 0.008% |
| Legitimate traffic challenged | 0.01% |
Timeline
The attack was preceded by a breaking political story. Request rates on the targeted routes exceeded their hourly baseline by a factor of 643 within 39 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 89 ms during the first minute, then normal service.
Recommendations
- Review allow-listed partner ranges quarterly.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Keep origin IPs out of public DNS history.