The built-in Microsoft password complexity filter must be enabled.

STIG ID: WN10-AC-000040  |  SRG: SRG-OS-000069-GPOS-00037 |  Severity: medium |  CCI: CCI-000366 |  Vulnerability Id: V-220746 | 

Vulnerability Discussion

The use of complex passwords increases their strength against guessing and brute-force attacks. This setting configures the system to verify that newly created passwords conform to the Windows password complexity policy.

Check

Verify the effective setting in Local Group Policy Editor.
Run "gpedit.msc".

Navigate to Local Computer Policy >> Computer Configuration >> Windows Settings >> Security Settings >> Account Policies >> Password Policy.

If the value for "Password must meet complexity requirements" is not set to "Enabled", this is a finding.

If the site is using a password filter that requires this setting be set to "Disabled" for the filter to be used, this would not be considered a finding.

Fix

Configure the policy value for Computer Configuration >> Windows Settings >> Security Settings >> Account Policies >> Password Policy >> "Password must meet complexity requirements" to "Enabled".