The next major version of Adobe s PDF Reader will feature new sandboxing technology aimed at curbing a surge in malicious hacker attacks against the software. The security feature, called Protected Mode, is similar to the Google Chrome sandbox and Microsoft Office 2010 Protected Viewing Mode. The sandbox will be turned on by default and will display all operations in a PDF file in a very restricted manner. It will not protect users against phishing, clickjacking, weak cryptography or unauthorized network access.
Source: https://threatpost.com/protected-mode-brings-sandbox-adobe-reader-072010/74231/