MFA stands for multi-factor authentication, which is a method of verifying a user's identity by requiring two or more pieces of evidence, such as something the user knows (e.g., password), something the user has (e.g., token), or something the user is (e.g., fingerprint). MFA is the best control to help prevent credential stuffing attacks from being successful, because even if an attacker obtains a valid username and password from a breached site, they would still need another factor to access the target site. SIEM, IDS, and TLS are other security controls, but they are not as effective as MFA for preventing credential stuffing attacks. Reference: https://www.cloudflare.com/learning/bots/what-is-credential-stuffing/