Developer website: objective-see llc
Ostiarius is tool for El Capitan that blocks unsigned internet binaries from executing.
Though OS X's Gatekeeper attempts to provide this functionality, I discovered it was trivial to bypass. The bypass was detailed in: 'Gatekeeper Exposed'.
What's New
Version 1.2.0:
- OS X 10.11.6 compatibility
Requirements
- OS X 10.11 or later