On Saturday 23 October 2021 at 04:15 UTC, a search endpoint flood targeted a fashion retail customer in Central Europe. The attack peaked at 501.9 million requests per second and lasted 51 minutes. Traffic originated from 2438 autonomous systems in 61 countries, predominantly hijacked home routers.
| Vector | search endpoint flood |
| Peak | 501.9 million requests per second |
| Duration | 51 min |
| Time to mitigation | 0.474 s |
| Attack traffic reaching origin | 0.029% |
| Legitimate traffic challenged | 0.27% |
Timeline
The attack was preceded by a publicly announced sales event. Request rates on the targeted routes exceeded their hourly baseline by a factor of 403 within 33 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
- Add a dedicated rate limit for the targeted route.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable authenticated origin pulls.
Thanks — sharing this with our on-call team.
Thanks! Yes — the risk score and its components are included in every log record.
Great write-up. We saw almost the same pattern on our login endpoint last month.
Solid runbook advice. The DNS-at-2am point hit home.
Great write-up. We saw almost the same pattern on our login endpoint last month.
Thanks — sharing this with our on-call team.
Our auditors asked for exactly this kind of incident evidence under DORA.
Our auditors asked for exactly this kind of incident evidence under DORA.
This matches what we see in iGaming around big matches.