Information
Protected Mode is a 'sandbox' that is essentially a read-only mode. When enabled, Acrobat allows the execution environment of untrusted PDF's and the processes the PDF may invoke but also presumes all PDFs are potentially malicious and confines processing to a restricted sandbox.
Solution
Configure the following registry value:
Registry Hive:
HKEY_LOCAL_MACHINE
Registry Path:
\Software\Policies\Adobe\Adobe Acrobat\2015\FeatureLockDown
Value Name: bProtectedMode
Type: REG_DWORD
Value: 1
Configure the policy value for Computer Configuration > Administrative Templates > Adobe Acrobat Pro DC Classic > Preferences > 'Protected Mode' to 'Enabled'.
This policy setting requires the installation of the AcrobatProDCClassic custom templates included with the STIG package. 'AcrobatProDCClassic.admx' and 'AcrobatProDCClassic.adml' must be copied to the \Windows\PolicyDefinitions and \Windows\PolicyDefinitions\en-US directories respectively.