On Wednesday 23 June 2021 at 02:26 UTC, a HTTP GET flood targeted a developer platform customer in the UK. The attack peaked at 890.2 million requests per second and lasted 56 minutes. Traffic originated from 3009 autonomous systems in 17 countries, predominantly compromised cloud VMs.
| Vector | HTTP GET flood |
| Peak | 890.2 million requests per second |
| Duration | 56 min |
| Time to mitigation | 0.279 s |
| Attack traffic reaching origin | 0.041% |
| Legitimate traffic challenged | 0.44% |
Timeline
The attack was preceded by no stated motive. Request rates on the targeted routes exceeded their hourly baseline by a factor of 546 within 7 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 216 ms during the first minute, then normal service.
Recommendations
- Enable authenticated origin pulls.
- Enable log streaming to your SIEM for faster correlation.
- Add a dedicated rate limit for the targeted route.