On Tuesday 29 April 2025 at 11:49 UTC, a credential stuffing targeted a crypto exchange customer in Central Europe. The attack peaked at 320.5 million requests per second and lasted 187 minutes. Traffic originated from 1060 autonomous systems in 32 countries, predominantly compromised cloud VMs.
| Vector | credential stuffing |
| Peak | 320.5 million requests per second |
| Duration | 187 min |
| Time to mitigation | 0.898 s |
| Attack traffic reaching origin | 0.068% |
| Legitimate traffic challenged | 0.42% |
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 59 within 31 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 141 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.