On Saturday 23 December 2023 at 23:59 UTC, a HTTP POST flood targeted a ticketing customer in the Nordics. The attack peaked at 956.3 million requests per second and lasted 56 minutes. Traffic originated from 437 autonomous systems in 70 countries, predominantly compromised cloud VMs.
| Vector | HTTP POST flood |
| Peak | 956.3 million requests per second |
| Duration | 56 min |
| Time to mitigation | 0.910 s |
| Attack traffic reaching origin | 0.013% |
| Legitimate traffic challenged | 0.31% |
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 619 within 31 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
- Keep origin IPs out of public DNS history.
- Add a dedicated rate limit for the targeted route.
- Review allow-listed partner ranges quarterly.