Protected Mode in Adobe Reader X is enabled by default and malicious PDF documents can't launch arbitrary executable files or write to.
Flash protected mode is an Adobe security feature for Firefox on Windows Vista and above. Disable it if the Flash plugin crashes or hangs.
Protected Mode (PM) was introduced with Reader 10.0 on Windows. It transparently protects users against attacks by sandboxing application.
Adobe Reader X - Protected Mode Disable ADM
Adobe protected mode - border-color: