What is a risk associated with using password lockout on internet-facing accounts?

Using password lockout mechanisms on internet-facing accounts can lead to denial of service (DoS) conditions as a legitimate risk. When a user unsuccessfully attempts to log in multiple times, the lockout feature triggers, preventing further access. If an attacker intentionally targets an account with repeated failed login attempts, this mechanism can lock the account, thereby denying access not just to the attacker but also to the legitimate user. In scenarios where important accounts are locked out following multiple unsuccessful login attempts, users could be unable to perform essential functions, which can be particularly detrimental for critical systems or services.

This risk emphasizes the balance needed in authentication mechanisms: while lockout policies can prevent unauthorized access through repeated guessing attempts, they can inadvertently disrupt service availability for legitimate users and create frustration. Thus, careful consideration is necessary to implement such policies without compromising service accessibility.