On Sunday 28 April 2024 at 21:51 UTC, a cache-busting query flood targeted a retail banking customer in North America. The attack peaked at 498.2 million requests per second and lasted 59 minutes. Traffic originated from 2856 autonomous systems in 111 countries, predominantly a Mirai-derived IoT botnet.
| Vector | cache-busting query flood |
| Peak | 498.2 million requests per second |
| Duration | 59 min |
| Time to mitigation | 0.480 s |
| Attack traffic reaching origin | 0.033% |
| Legitimate traffic challenged | 0.41% |
Timeline
The attack was preceded by a competitor’s product launch. Request rates on the targeted routes exceeded their hourly baseline by a factor of 205 within 20 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
- Keep origin IPs out of public DNS history.
- Review allow-listed partner ranges quarterly.
- Enable authenticated origin pulls.