On Tuesday 16 March 2021 at 11:23 UTC, a credential stuffing targeted a education platform customer in Southeast Asia. The attack peaked at 319.9 million requests per second and lasted 163 minutes. Traffic originated from 2709 autonomous systems in 46 countries, predominantly residential proxy networks.
| Vector | credential stuffing |
| Peak | 319.9 million requests per second |
| Duration | 163 min |
| Time to mitigation | 0.455 s |
| Attack traffic reaching origin | 0.010% |
| Legitimate traffic challenged | 0.37% |
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 816 within 21 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
- Enable log streaming to your SIEM for faster correlation.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Review allow-listed partner ranges quarterly.
Do you publish the edge IP ranges in a machine-readable format?
Great to hear, thanks for sharing your experience.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.
Thanks — sharing this with our on-call team.