Brute force attacks are cyberattacks where attackers attempt to guess shared secrets like passwords or encryption keys by systematically trying every possible combination, often using automation, exploit kits, and botnets. These attacks can be online, where attackers try numerous username-password combinations on login forms, or offline, where they decrypt password hashes without triggering security measures. Various forms of brute force attacks exist, including simple, dictionary, reverse, hybrid, rainbow table, password spraying, and credential stuffing, each with distinct methods of guessing or using stolen credentials. Prevention strategies include implementing passwordless authentication, multi-factor authentication (MFA), and enforcing stringent password and login hygiene, such as complex password requirements, account lockout after failed attempts, and CAPTCHA checks. These measures help mitigate the risk and impact of brute force attacks, which are often the initial entry point for more extensive cyberattacks.