On Sunday 26 June 2022 at 19:34 UTC, a Slowloris targeted a ticketing customer in Southeast Asia. The attack peaked at 475.5 million requests per second and lasted 64 minutes. Traffic originated from 3636 autonomous systems in 117 countries, predominantly a headless-browser farm.
| Vector | Slowloris |
| Peak | 475.5 million requests per second |
| Duration | 64 min |
| Time to mitigation | 0.767 s |
| Attack traffic reaching origin | 0.048% |
| Legitimate traffic challenged | 0.39% |
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 865 within 36 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.
- Keep origin IPs out of public DNS history.
Any plans to support per-tenant limits keyed on a JWT claim?
We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.
Great to hear, thanks for sharing your experience.
Nice to read a vendor blog that admits what went wrong.
Solid runbook advice. The DNS-at-2am point hit home.
The point about origin IPs leaking through certificate transparency logs is underrated.
Thanks — sharing this with our on-call team.
We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.
Thanks — sharing this with our on-call team.