• Requirement

    Enforce a minimum password complexity and change of characters when new passwords are created.

  • Discussion

    This requirement applies to single-factor authentication of individuals using passwords as individual or group authenticators, and in a similar manner, when passwords are used as part of multifactor authenticators. The number of changed characters refers to the number of changes required with respect to the total number of positions in the current password. To mitigate certain brute force attacks against passwords, organizations may also consider salting passwords.

More Info

  • Title

    Password Complexity
  • Domain

    Identification and Authentication
  • CMMC Level

  • Related NIST 800-171 ID

  • Related NIST 800-53 ID


  • DoD Scoring Methodology Points


  • Reference Documents

    • N/A

  • Further Discussion

    Password complexity means using different types of characters as well as a specified number of characters. This applies to both the creation of new passwords and the modification of existing passwords. Characters to manage complexity include numbers, lowercase and uppercase letters, and symbols. Minimum complexity requirements are left up to the organization to define. Define the lowest level of password complexity required. Define the number of characters that must be changed when an existing password is changed. Enforce these rules for all passwords. Salting passwords adds a string of random characters (salt) to a password prior to hashing. This ensures the randomness of the resulting hash value.


    You work with management to define password complexity rules and ensure they are listed in the company’s security policy. You define and enforce a minimum number of characters for each password and ensure that a certain number of characters must be changed when updating passwords [a,b]. Characters include numbers, lowercase and uppercase letters, and symbols [a]. These rules help create hard-to-guess passwords, which help to secure your network.

    Potential Assessment Considerations

    • Is a degree of complexity specified for passwords, (e.g., are account passwords a minimum of 12 characters and a mix of upper/lower case, numbers, and special characters), including minimum requirements for each type [a,b,c]?
    • Is a change of characters required when new passwords are created [d]?

NIST 800-171A Assessment Guidance

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