On Tuesday 12 November 2024 at 04:17 UTC, a Slowloris targeted a news publisher customer in North America. The attack peaked at 569.1 million requests per second and lasted 135 minutes. Traffic originated from 3671 autonomous systems in 31 countries, predominantly a headless-browser farm.
| Vector | Slowloris |
| Peak | 569.1 million requests per second |
| Duration | 135 min |
| Time to mitigation | 0.657 s |
| Attack traffic reaching origin | 0.058% |
| Legitimate traffic challenged | 0.15% |
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 751 within 15 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 105 ms during the first minute, then normal service.
Recommendations
- Enable log streaming to your SIEM for faster correlation.
- Enable authenticated origin pulls.
- Keep origin IPs out of public DNS history.
Nice to read a vendor blog that admits what went wrong.
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.
Our auditors asked for exactly this kind of incident evidence under DORA.
Verified good bots and allow-listed partners bypass challenges entirely.