On Monday 3 April 2023 at 17:27 UTC, a search endpoint flood targeted a tax authority portal customer in Iberia. The attack peaked at 929.3 million requests per second and lasted 81 minutes. Traffic originated from 2076 autonomous systems in 94 countries, predominantly a rented booter service.
| Vector | search endpoint flood |
| Peak | 929.3 million requests per second |
| Duration | 81 min |
| Time to mitigation | 0.300 s |
| Attack traffic reaching origin | 0.054% |
| Legitimate traffic challenged | 0.53% |
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 376 within 34 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 22 ms during the first minute, then normal service.
Recommendations
- Enable log streaming to your SIEM for faster correlation.
- Review allow-listed partner ranges quarterly.
- Lower challenge thresholds on authentication endpoints during high-risk events.
Our auditors asked for exactly this kind of incident evidence under DORA.