CVE-2016-4997

Las implementaciones de compat IPT_SO_SET_REPLACE y IP6T_SO_SET_REPLACE setsockopt en el subsistema netfilter en el kernel de Linux antes de 4.6.3 permiten a los usuarios locales obtener privilegios o provocar una denegación de servicio (corrupción de memoria) aprovechando el acceso del root en el contenedor para proporcionar un valor de compensación manipulado que desencadena una disminución no intencionada.

A flaw was discovered in processing setsockopt for 32 bit processes on 64 bit systems. This flaw will allow attackers to alter arbitrary kernel memory when unloading a kernel module. This action is usually restricted to root-privileged users but can also be leveraged if the kernel is compiled with CONFIG_USER_NS and CONFIG_NET_NS and the user is granted elevated privileges.

It was discovered that the stack guard page for processes in the Linux kernel was not sufficiently large enough to prevent overlapping with the heap. An attacker could leverage this with another vulnerability to execute arbitrary code and gain administrative privileges Jesse Hertz and Tim Newsham discovered that the Linux netfilter implementation did not correctly perform validation when handling 32 bit compatibility IPT_SO_SET_REPLACE events on 64 bit platforms. A local unprivileged attacker could use this to cause a denial of service or execute arbitrary code with administrative privileges. Various other issues were also addressed.