This policy setting determines the least number of characters that make up a password for a user account. There are many different theories about how to determine the best password length for an organization, but perhaps 'pass phrase' is a better term than 'password.' In Microsoft Windows 2000 or later, pass phrases can be quite long and can include spaces. Therefore, a phrase such as 'I want to drink a $5 milkshake' is a valid pass phrase; it is a considerably stronger password than an 8 or 10 character string of random numbers and letters, and yet is easier to remember. Users must be educated about the proper selection and maintenance of passwords, especially with regard to password length. In enterprise environments, the ideal value for the Minimum password length setting is 14 characters, however you should adjust this value to meet your organization's business requirements. Countermeasure: Configure the Minimum password length setting to a value of 14 or more. If the number of characters is set to 0, no password will be required. In most environments, we recommend a 14-character password because it is long enough to provide adequate security but not too difficult for users to easily remember. This configuration provides adequate defense against a brute force attack. Using the Passwords must meet complexity requirements setting in addition to the Minimum password length setting helps reduce the possibility of a dictionary attack. Potential Impact: Requirements for extremely long passwords can actually decrease the security of an organization, because users might leave the information in an insecure location or lose it. If very long passwords are required, mistyped passwords could cause account lockouts and increase the volume of help desk calls. If your organization has issues with forgotten passwords due to password length requirements, consider teaching your users about pass phrases, which are often easier to remember and, due to the larger number of character combinations, much harder to discover. Note: Older versions of Windows such as Windows 98 and Windows NT 4.0 do not support passwords that are longer than 14 characters. Computers that run these older operating systems are unable to authenticate with computers or domains that use accounts that require long passwords.

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(1) GPO: Computer Configuration\\Windows Settings\\Security Settings\\Account Policies\\Password Policy\\Minimum password length (2) REG: ### (3) WMI: root\\rsop\\computer#RSOP_SecuritySettingNumeric#Setting#KeyName = 'MinimumPasswordLength' And precedence=1