A zero-day attack or threat exploits a previously unknown vulnerability in a computer application, meaning that the attack occurs on “day zero” of awareness of the vulnerability; thus, developers have had zero days to address and patch it. Zero-day exploits — the software and/or strategies to carry out a successful attack — are used or shared by attackers.
Solutions such as Palo Alto Networks’ WildFire are typically an adjunct subscription to existing firewalls. They actively analyze network traffic it in a safe, cloud-based virtual environment to observe the behavior of malicious malware. Through these a subscription services, updates are automatically generated and distributed to installed firewalls for global protection against the newly discovered malware.