On Friday 10 March 2023 at 22:08 UTC, a credential stuffing targeted a retail banking customer in the Nordics. The attack peaked at 326.7 million requests per second and lasted 31 minutes. Traffic originated from 4057 autonomous systems in 89 countries, predominantly a Mirai-derived IoT botnet.
| Vector | credential stuffing |
| Peak | 326.7 million requests per second |
| Duration | 31 min |
| Time to mitigation | 0.695 s |
| Attack traffic reaching origin | 0.089% |
| Legitimate traffic challenged | 0.66% |
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 465 within 26 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
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Enable authenticated origin pulls.
- Add a dedicated rate limit for the targeted route.
- Keep origin IPs out of public DNS history.