Linus Torvalds released a Linux kernel update last week which fixes a flaw in the access control to memory. Shortly afterwards, exploits appeared making it possible to gain root privileges using this error.
Since Linux kernel version 2.6.39 the dump of each process can be viewed in /proc/<pid>/mem and even written to. Before 2.6.39, an #ifdef in the code had prevented writing, but in 2.6.39, the checks had been deemed adequate, so the #ifdef was removed. Those checks, to ensure that only processes with the correct permission could write to the memory, instead proved inadequate and could be easily fooled.
Shortly after the publication of an explanatory article on Nerdling Sapple, other coders used the information contained in the article to create exploits and made them available on the net. The exploit works by manipulating the virtual working memory of a setuid root program such as su and can give a regular user of a Linux system root privileges. Jay Freeman – known as Saurik in the iPhone jailbreak community – even has a working version for Android.
read more..........http://www.h-online.com/security/news/item/Linux-root-exploit-due-to-memory-access-Update-2-1419834.html