A technician needs to strengthen security controls against brute-force attacks.

Multifactor authentication (MFA) significantly enhances security by requiring two or more forms of verification before granting access to an account or system. This method is highly effective against brute-force attacks, where attackers attempt to guess a user's password through repeated trials. By implementing MFA, even if a password is compromised, unauthorized access is still prevented without the additional authentication factor(s), such as a code from a smartphone app, a fingerprint, or a physical security token.

Multifactor authentication: Provides an additional layer of security beyond just the password, making it much harder for attackers to gain unauthorized access through brute-force methods, as they would need to compromise more than one authentication factor.

Encryption (B) is crucial for protecting data at rest and in transit, but it does not directly prevent brute-force login attempts. Increased password complexity (C) can deter brute-force attacks by making passwords harder to guess, but it is not as effective as MFA in preventing access when passwords are compromised. A secure password vault (D) helps users manage and store their passwords securely, which can indirectly contribute to security by allowing users to keep more complex passwords, but it does not directly prevent brute-force attacks on accounts.