On Saturday 25 December 2021 at 02:21 UTC, a HTTP POST flood targeted a crypto exchange customer in the Middle East. The attack peaked at 210.0 million requests per second and lasted 75 minutes. Traffic originated from 2567 autonomous systems in 113 countries, predominantly a headless-browser farm.
| Vector | HTTP POST flood |
| Peak | 210.0 million requests per second |
| Duration | 75 min |
| Time to mitigation | 0.281 s |
| Attack traffic reaching origin | 0.081% |
| Legitimate traffic challenged | 0.72% |
Timeline
The attack was preceded by an extortion email received two days earlier. Request rates on the targeted routes exceeded their hourly baseline by a factor of 73 within 16 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
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable authenticated origin pulls.
- Keep origin IPs out of public DNS history.
We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.
Could you share the dataset behind the percentages?
Great write-up. We saw almost the same pattern on our login endpoint last month.
Could you share the dataset behind the percentages?
Our auditors asked for exactly this kind of incident evidence under DORA.
Thanks — sharing this with our on-call team.