Defined Minimum Changed Characters for Passwords, v1.0

Defines conformance and assessment criteria for compliance with minimum security requirements for defined minimum changed characters for passwords as related to overall identification and authentication requirements.
If an assessment step references organization-defined elements (E.g. <organization-defined personnel or roles>, <organization-defined frequency>, etc.), corresponding citations/excerpts must be provided to confirm that the organization has established and documented these values and that they apply as referenced in the conformance criteria.

Similarly, if a "Selection" among multiple options (e.g. [Selection (one or more): as needed; ]) is specified, evidence must be provided to establish that the option(s) implemented by the organization have been defined and documented.

The assessment step shall not be marked as satisfied without this evidence.

Assessment Step

1
Defined Minimum Changed Characters for Passwords (DefinedMinimumChangedCharactersforPasswords)
For password-based authentication, does the information system enforce at least the following number of changed characters when new passwords are created: <organization-defined number>?
Artifact
A1
Provide evidence (e.g. organizational policies, procedures, compliance/assessment reports, etc.) that support the assessor's response to this assessment step.
Parameter
Minimum Changed Charactersrequired
NUMBER : Provide the minimum number of characters that new passwords must have that are different from the previous password.
If conformance criteria reference organization-defined elements (e.g. <organization-defined personnel or roles>, <organization-defined frequency>, etc.), these values must be defined and documented by the organization.

Similarly, if the criteria specify a "Selection" among multiple options (e.g. [Selection (one or more): as needed; ]), the option(s) implemented by the organization must also be defined and documented.

Conformance Criteria (1)

C1
For password-based authentication, the information system must enforce at least the following number of changed characters when new passwords are created: <organization-defined number>.
Citation
SP800-53R4
Appendix F, IA-5 (1)