On Sunday 26 January 2025 at 13:05 UTC, a WebSocket connection flood targeted a education platform customer in the Nordics. The attack peaked at 802.7 million requests per second and lasted 31 minutes. Traffic originated from 1604 autonomous systems in 56 countries, predominantly a headless-browser farm.
| Vector | WebSocket connection flood |
| Peak | 802.7 million requests per second |
| Duration | 31 min |
| Time to mitigation | 0.294 s |
| Attack traffic reaching origin | 0.086% |
| Legitimate traffic challenged | 0.15% |
Timeline
The attack was preceded by a competitor’s product launch. Request rates on the targeted routes exceeded their hourly baseline by a factor of 886 within 12 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
No customer-visible impact. The on-call engineer was notified and acknowledged the incident from the dashboard.
Recommendations
- Add a dedicated rate limit for the targeted route.
- Review allow-listed partner ranges quarterly.
- Enable log streaming to your SIEM for faster correlation.
Nice to read a vendor blog that admits what went wrong.
Carpet bombing is nasty. Good to see a clear explanation of it.
Good question. We will cover that in a follow-up post.