Ethical Hacking Essentials Practice Test

Zero-day vulnerabilities are security flaws that are exploited by attackers before the software developers have had the opportunity to create and release a patch to fix the flaw. The term "zero-day" refers to the fact that the developers have had zero days to address the vulnerability since it was discovered or reported. These vulnerabilities pose a significant risk because they are unknown to the security community and can be exploited without any warning. Attackers can use such vulnerabilities to gain unauthorized access, execute malicious code, or conduct other harmful activities.

In contrast, exploit vulnerabilities typically refer to the tools or techniques used to take advantage of a vulnerability, rather than the vulnerability itself. Legacy vulnerabilities are those found in outdated systems or software that are no longer supported with updates, while public vulnerabilities are those that have been disclosed to the public and for which patches are already available. Zero-day vulnerabilities remain critical because they represent a window of opportunity for attackers to exploit systems before any defense can be deployed.