Signing in using a PIN must be turned off.

From Windows 8 Security Technical Implementation Guide

Associated with IA controls: IAIA-1

SV-48312r1_rule Signing in using a PIN must be turned off.

Vulnerability discussion

Strong sign-on must be used to protect a system. The PIN feature is limited to 4 numbers and caches the domain password in the system vault.

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Fix text

Configure the policy value for Computer Configuration -> Administrative Templates -> System -> Logon -> "Turn on PIN sign-in" to "Disabled".

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