On Thursday 2 December 2021 at 05:28 UTC, a HTTP GET flood targeted a tax authority portal customer in Latin America. The attack peaked at 31.0 million requests per second and lasted 59 minutes. Traffic originated from 498 autonomous systems in 67 countries, predominantly mobile carrier ranges.
| Vector | HTTP GET flood |
| Peak | 31.0 million requests per second |
| Duration | 59 min |
| Time to mitigation | 0.870 s |
| Attack traffic reaching origin | 0.053% |
| Legitimate traffic challenged | 0.39% |
Timeline
The attack was preceded by a breaking political story. Request rates on the targeted routes exceeded their hourly baseline by a factor of 182 within 27 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 198 ms during the first minute, then normal service.
Recommendations
- Enable log streaming to your SIEM for faster correlation.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Review allow-listed partner ranges quarterly.
Do you publish the edge IP ranges in a machine-readable format?
Could you share the dataset behind the percentages?
How does the proof-of-work challenge behave on older Android devices? Any numbers below Android 10?
Machine-readable ranges are at /ips.json and via the API.
Our auditors asked for exactly this kind of incident evidence under DORA.
Do you publish the edge IP ranges in a machine-readable format?