This counts CIFS authentication attempts blocked because the presented password field violated a configured length policy. This typically catches malformed or crafted authentication packets, a technique sometimes used by SMB exploit tools or brute-force scripts that send oddly sized credential fields, rather than an ordinary user mistyping a password, since normal clients send properly formed credential fields. For example, a burst of these violations coinciding with an automated tool probing an SMB share using malformed authentication packets.