On Tuesday 16 April 2024 at 08:19 UTC, a Slowloris targeted a electronics retail customer in the Benelux. The attack peaked at 601.7 million requests per second and lasted 145 minutes. Traffic originated from 4200 autonomous systems in 109 countries, predominantly residential proxy networks.
| Vector | Slowloris |
| Peak | 601.7 million requests per second |
| Duration | 145 min |
| Time to mitigation | 0.687 s |
| Attack traffic reaching origin | 0.051% |
| Legitimate traffic challenged | 0.23% |
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 437 within 9 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.
- Enable log streaming to your SIEM for faster correlation.
- Review allow-listed partner ranges quarterly.
Thanks — sharing this with our on-call team.
Great write-up. We saw almost the same pattern on our login endpoint last month.
Thanks! Yes — the risk score and its components are included in every log record.
The billing model is what got our finance team on board, honestly.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.
Our auditors asked for exactly this kind of incident evidence under DORA.
Machine-readable ranges are at /ips.json and via the API.
This matches what we see in iGaming around big matches.