On Sunday 30 July 2023 at 01:51 UTC, a cache-busting query flood targeted a municipal services customer in Southeast Asia. The attack peaked at 845.4 million requests per second and lasted 59 minutes. Traffic originated from 2784 autonomous systems in 64 countries, predominantly a Mirai-derived IoT botnet.
| Vector | cache-busting query flood |
| Peak | 845.4 million requests per second |
| Duration | 59 min |
| Time to mitigation | 0.079 s |
| Attack traffic reaching origin | 0.065% |
| Legitimate traffic challenged | 0.08% |
Timeline
The attack was preceded by a hacktivist channel announcing the target. Request rates on the targeted routes exceeded their hourly baseline by a factor of 558 within 24 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 authenticated origin pulls.
- Enable log streaming to your SIEM for faster correlation.
- Keep origin IPs out of public DNS history.