On Friday 21 October 2022 at 22:18 UTC, a Slowloris targeted a B2B SaaS customer in Southeast Asia. The attack peaked at 382.0 million requests per second and lasted 160 minutes. Traffic originated from 1206 autonomous systems in 15 countries, predominantly compromised cloud VMs.
| Vector | Slowloris |
| Peak | 382.0 million requests per second |
| Duration | 160 min |
| Time to mitigation | 0.149 s |
| Attack traffic reaching origin | 0.040% |
| Legitimate traffic challenged | 0.68% |
Timeline
The attack was preceded by a competitor’s product launch. Request rates on the targeted routes exceeded their hourly baseline by a factor of 251 within 32 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
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Enable log streaming to your SIEM for faster correlation.
- Keep origin IPs out of public DNS history.
- Review allow-listed partner ranges quarterly.
Carpet bombing is nasty. Good to see a clear explanation of it.
Our auditors asked for exactly this kind of incident evidence under DORA.
Good question. We will cover that in a follow-up post.