Common mistakes in authentication often involve failing to properly hash and salt passwords, leading to vulnerable credentials when breaches occur, and implementing weak password policies . Another frequent issue is improper session management , such as not expiring sessions effectively or failing to regenerate session IDs after login, which can enable session hijacking. A critical oversight is the absence of multi-factor authentication (MFA), leaving accounts susceptible to credential stuffing and phishing attacks. Furthermore, many systems feature flawed password reset mechanisms, often lacking rate-limiting or using easily guessable tokens, creating direct pathways for account takeover. Neglecting rate-limiting on login attempts and other sensitive operations, alongside displaying overly verbose error messages that leak sensitive information, are also significant vulnerabilities that attackers exploit.