On Saturday 12 June 2021 at 02:11 UTC, a search endpoint flood targeted a tax authority portal customer in Central Europe. The attack peaked at 820.4 million requests per second and lasted 52 minutes. Traffic originated from 670 autonomous systems in 9 countries, predominantly residential proxy networks.
| Vector | search endpoint flood |
| Peak | 820.4 million requests per second |
| Duration | 52 min |
| Time to mitigation | 0.945 s |
| Attack traffic reaching origin | 0.086% |
| Legitimate traffic challenged | 0.54% |
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 383 within 40 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
- Review allow-listed partner ranges quarterly.
- Enable log streaming to your SIEM for faster correlation.
- Keep origin IPs out of public DNS history.