What should a web application developer implement to limit failed login attempts and mitigate brute force attacks?

To effectively limit failed login attempts and mitigate brute force attacks, implementing limits on the number of login attempts is a crucial strategy. This approach directly addresses the vulnerability that brute force attacks exploit, which typically involves systematically trying multiple combinations of usernames and passwords.

By setting limits, the application can restrict the number of consecutive failed login attempts from a single user or IP address. Once the threshold is reached, additional login attempts can be temporarily blocked, encouraging users to take appropriate security measures, such as recovering their passwords instead of continuously attempting retries. This not only reduces the risk of unauthorized access but also makes it more cumbersome and time-consuming for attackers to execute brute force methods.

While multifactor authentication (MFA) strengthens security by requiring additional verification beyond just a password, it does not specifically limit failed login attempts. Similarly, enabling features like ASLR enhances the security posture of applications by making it harder for attackers to predict memory addresses, but it also does not protect against brute force attempts at the login stage. Password checks can ensure that users create strong passwords but do not address the issue of limiting multiple failed logins.

Therefore, implementing limits on login attempts is a proactive measure tailored specifically to counter brute force attacks and enhance the overall security of web applications.