In a move that is designed to make playing Flash content on your Mac more secure, Adobe has announced that Flash Player is sandboxed in Safari on OS X Mavericks. A sandbox profile for the Flash plugin was created by Adobe for inclusion in the Webkit project, with Webkit being the browser engine behind the scenes in Safari.
How does the sandbox profile work? It basically tells Webkit (and thus Safari) to allow the plugin to only read and write files to specific items, limiting just how much damage a malicious attacker could do when taking over control of Flash through a vulnerability. This keeps Flash-based infections from being able to persist for any length of time, and should also keep attackers from affecting other apps.
Adobe's products, including Flash Player, the Reader program and Acrobat, used to be prime targets for attackers, but sandboxing and other security work has made them less attractive to the bad guys.