Original URL: http://www.theregister.co.uk/2012/12/17/samsung_exynos_flaw/

Samsung mobes pwned by ANY APP, thanks to chip code hole

Cluster of Exynos-powered Galaxies and other gear at risk

By Simon Sharwood

Posted in Security, 17th December 2012 06:19 GMT

A member of an XDA developers forum who calls him-or-herself Alephzain claims to have found a flaw in several Samsung handsets and tablets that could allow attackers to enjoy full access to their RAM.

Alephzain posted news of the embarrassing bug here, stating: “The security hole is in [the] kernel, exactly with the device /dev/exynos-mem.”

Thanks to exynos-mem's wide-open file system permissions, it can be read from and written to by any software running on the handheld, acting as a portal to the device's physical memory and allowing malicious code to do pretty much anything it wants.

Exynos refers to the Samsung ARM-powered processor found in a great many of its Linux-powered Android devices, which can be compromised by the kernel flaw.

Alephzain's asessment of the bug follows:

The good news is we can easily obtain root on these devices and the bad is there is no control over it.

Ram dump, kernel code injection and others could be possible via app installation from Play Store. It certainly exists many ways to do that but Samsung give an easy way to exploit. This security hole is dangerous and expose phone to malicious apps.

Exploitation with native C and JNI could be easily feasible.

The flaw has attracted attention from others in the same forums, one of which – Chainfire - has thoughtfully provided an exploit for the flaw and warned “any app can use it to gain root without asking and without any permissions on a vulnerable device”, adding “let's hope for some fixes ASAP".

Devices in trouble are said to include the Galaxy SIII, Galaxy Note, Galaxy Note 2 and Galaxy 10.1 tablets.

Members of the XDA developers community are evidently quite keen on the flaw, as it will allow them to do some low level hacking on their preferred Samsung devices. Community members say they've told Samsung about the problem, which should allow the rest of us to Keep Calm and Not Download Apps until a fix is issued. ®