CVE-2015-5754

Vulnerabilidad de condición de carrera en hilos corriendo en Install.framework en el componente Install Framework Legacy en Apple OS X en versiones anteriores a 10.10.5, permite a atacantes ejecutar código arbitrario en un contexto con privilegios a través de una aplicación manipulada que aprovecha la caída incorrecta de privilegios asociada a un error de bloqueo.

The Install.framework runner suid root binary does not correctly account for the fact that Distributed Objects can be connected to by multiple clients at the same time. By connecting two proxy objects to an IFInstallRunner and calling [IFInstallRunner makeReceiptDirAt:asRoot:] in the first and passing a custom object as the directory name we can get a callback to our code just after the makeReceiptDirAt code has called seteuid(0);setguid(0) to regain privs. Since BSD priviledges are per-process this means that our other proxy object will now have euid 0 without having to provide an authorization reference. In this second proxy we can then just call runTaskSecurely and get a root shell before returning from the first proxy's callback function which will then drop privs.