A zero-day exploit is an undisclosed vulnerability in your hardware, software, or network that has been exposed with no current remedy. While developers are working on a patch, hackers enjoy free reign to exploit the vulnerability at will. While you can t patch an unknown vulnerability, you can detect potential attacks by monitoring your network for unusual or unprecedented activity. A cloud-based security operations center (SOC), such as the Arctic Wolf SOC-as-a-service, can monitor your on-premise and cloud resources in real-time, 24/7.
Source: https://threatpost.com/understanding-the-risk-of-zero-day-exploits/151110/