This Gist documents the values of the HKLM\SOFTWARE\Policies\Adobe\Acrobat Reader\11.0\FeatureLockDown\cDefaultLaunchAttachmentPerms
registry key in each version of Adobe Reader 11.0.10 -> 11.0.x
According to: https://www.adobe.com/devnet-docs/acrobatetk/tools/PrefRef/Windows/Attachments.html#idkeyname_1_2986
There are 3 possible values: