On Tuesday 27 August 2024 at 15:42 UTC, a Slowloris targeted a developer platform customer in the UK. The attack peaked at 317.4 million requests per second and lasted 129 minutes. Traffic originated from 1102 autonomous systems in 109 countries, predominantly compromised cloud VMs.
| Vector | Slowloris |
| Peak | 317.4 million requests per second |
| Duration | 129 min |
| Time to mitigation | 0.554 s |
| Attack traffic reaching origin | 0.022% |
| Legitimate traffic challenged | 0.63% |
Timeline
The attack was preceded by a breaking political story. Request rates on the targeted routes exceeded their hourly baseline by a factor of 774 within 19 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
- Enable authenticated origin pulls.
- Review allow-listed partner ranges quarterly.
- Lower challenge thresholds on authentication endpoints during high-risk events.
The point about origin IPs leaking through certificate transparency logs is underrated.
Thanks! Yes — the risk score and its components are included in every log record.