Why is relying on weak passwords considered a security vulnerability?

Relying on weak passwords is considered a security vulnerability primarily because weak passwords are easy for hackers to guess or crack. Weak passwords often lack complexity and unpredictability, making them susceptible to various forms of attacks such as brute force attacks or dictionary attacks. In these attacks, a hacker systematically attempts to guess the password either by trying all possible combinations or by using a list of common or previously used passwords.

This vulnerability is significant because many users tend to choose simple passwords that are memorable, but this also makes them predictable. Passwords that utilize common phrases, sequential numbers, or keyboard patterns are particularly vulnerable, as they can be quickly narrowed down by attackers. Therefore, using strong, complex passwords—those that include a mix of letters, numbers, and special characters—is essential to enhance security and protect sensitive data from unauthorized access.