On Friday 6 August 2021 at 14:51 UTC, a cache-busting query flood targeted a education platform customer in North America. The attack peaked at 895.0 million requests per second and lasted 51 minutes. Traffic originated from 2259 autonomous systems in 43 countries, predominantly compromised cloud VMs.
| Vector | cache-busting query flood |
| Peak | 895.0 million requests per second |
| Duration | 51 min |
| Time to mitigation | 0.182 s |
| Attack traffic reaching origin | 0.012% |
| Legitimate traffic challenged | 0.58% |
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 677 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
A brief increase in p99 latency of 117 ms during the first minute, then normal service.
Recommendations
- Review allow-listed partner ranges quarterly.
- Enable log streaming to your SIEM for faster correlation.
- Keep origin IPs out of public DNS history.
Any plans to support per-tenant limits keyed on a JWT claim?