Disabling error messaging for authentication would be the best recommendation to decrease the likelihood that a malicious attacker will receive helpful information. Error messaging for authentication is a feature that displays an error message when a user enters an incorrect username or password. However, this feature can also provide useful information to an attacker who is trying to guess or brute-force valid credentials. For example, if the error message says "incorrect password for given username", then the attacker knows that the username is valid and only needs to focus on cracking the password. Disabling error messaging for authentication can help reduce this information leakage and make it harder for an attacker to succeed.