On Monday 5 April 2021 at 15:22 UTC, a Slowloris targeted a ticketing customer in the Middle East. The attack peaked at 427.5 million requests per second and lasted 35 minutes. Traffic originated from 3515 autonomous systems in 97 countries, predominantly mobile carrier ranges.
| Vector | Slowloris |
| Peak | 427.5 million requests per second |
| Duration | 35 min |
| Time to mitigation | 0.477 s |
| Attack traffic reaching origin | 0.004% |
| Legitimate traffic challenged | 0.58% |
Timeline
The attack was preceded by a hacktivist channel announcing the target. Request rates on the targeted routes exceeded their hourly baseline by a factor of 243 within 34 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
- Review allow-listed partner ranges quarterly.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable authenticated origin pulls.