Noticed this - this morning:
NTLM Credentials Theft via PDF Files - Check Point Research
Slightly more shocking though was Adobe Security's response to this exploit:
"“Thank you for checking in on this case. Microsoft issued an optional security enhancement [0] late last year that provides customers with the ability to disable NTLM SSO authentication as a method for public resources. With this mitigation available to customers, we are not planning to make changes in Acrobat.“"