django-password-policies-validator

django-password-policies-validator is a Django app to validate password complexity and prevent users from reusing previous passwords.

Quick start

1. Add "password_policies" to your INSTALLED_APPS setting like this:

   INSTALLED_APPS = [
       ...
       'password_policies',
   ]
   

2. Add validators to AUTH_PASSWORD_VALIDATORS setting:

   AUTH_PASSWORD_VALIDATORS = [
       ...
       {
           'NAME': 'password_policies.password_validation.ComplexityValidator',
       },
       {
           'NAME': 'password_policies.password_validation.ReusedPasswordValidator',
       },
       {
           'NAME': 'password_policies.password_validation.MinimumChangeIntervalValidator',
       },
   ]
   

3. Append PasswordExpirationMiddleware to MIDDLEWARE setting, note that this must be listed after the 'django.contrib.auth.middleware.AuthenticationMiddleware'

   MIDDLEWARE = [
       ...
       'django.contrib.auth.middleware.AuthenticationMiddleware',
       ...
       'password_policies.middleware.PasswordExpirationMiddleware',
   ]
   

4. Run python manage.py migrate to create the PasswordRecord models.

5. Start the development server and go to the "Change password" page to check how the new password policies applied.

The Validator classes

Custom options can be passed into validators by the following syntax

AUTH_PASSWORD_VALIDATORS = [
    ...
    {
        'NAME': 'password_policies.password_validation.ComplexityValidator',
        'OPTIONS': {
            'min_char_categories': 3,
            'min_numeric_chars': 2,
        }
    },
]

Available options of each validator and their default values are listed below.

ComplexityValidator(min_char_categories=4, min_numeric_chars=1, min_uppercase_chars=1, min_lowercase_chars=1, min_special_chars=1)

Validates that the password is complex enough by checking how many categories of characters it contains, or the count of certain category of characters. Characters are devided into four categories:

• Uppercase alphabet characters A-Z
• Lowercase alphabet characters a-z
• Numeric characters 0-9
• Non-alphanumeric (special) characters

min_char_categories

The minimum categories of characters that the password should contain out of the four categories above. Value should be between 1 and 4.

min_numeric_chars

The minimum count of numeric characters that the password should contain. Value should be 0 or any positive integer.

min_uppercase_chars

The minimum count of uppercase characters that the password should contain. Value should be 0 or any positive integer.

min_lowercase_chars

The minimum count of lowercase characters that the password should contain. Value should be 0 or any positive integer.

min_special_chars

The minimum count of special characters that the password should contain. Value should be 0 or any positive integer.

ReusedPasswordValidator(record_length=3)

Remembers the user's previous n passwords and validate the new password doed not repeat any of them.

record_length

The number of previous password records that the validator should compare against. Value should be any positive integer.

MinimumChangeIntervalValidator(min_interval=1)

Prevent the user from changing the password again within certain period of time. This is to avoid the user to bypass ReusedPasswordValidator and reuse the old password by changing passwords repeatedly in a short period of time.

min_interval

The minimum time interval (in days) of two consecutive password change attempts. Value should be any positive interger or float.

The PasswordExpirationMiddleware class

PasswordExpirationMiddleware

Checks the user's password-changing records, if the user's password is expired, redirect the user to the password-changing form and shows a warning message.

This middleware works for any urls under the admin application namespace and redirects to the password_change url under the same namespace of the page which the user is redirected from. Urls not under the admin application namespace are not redirected.

The password expires in 90 days by default, and the number can be set by providing setting PASSWORD_EXPIRATION_DAYS to an integer or float value in settings.py.