Microsoft was quick to brush off the debugging hack that allows locked-down Windows RT Surface slabs to run any unauthorised desktop software. But now the exploit has been packaged into a slick jailbreaking tool that can unlock a Redmond fondleslab in seconds.
A programmer going by the name of Netham45 has released RT Jailbreak Tool v1, a batch file that automates the Windows RT trick first revealed by security researcher C. L. Rokr.
Netham45 reckons you can jailbreak a slab in about 20 seconds just by running the runExploit.bat file on the tablet and pressing a button, although it may ask a few "self-explanatory" questions afterwards.
The hack lets users install and run any desktop software of their choosing on Microsoft's Surface tablet-laptops and any other Windows RT devices. The Redmond giant wanted punters to only use cryptographically signed apps obtained from the official Windows Store, rather than any old program compiled for RT, the ARM port of Windows 8. The jailbreak hack simply disables this security signature check.
Netham45 has published a list of desktop apps recompiled to run on hacked Windows RT devices, here and here.
Rokr's hack required the Windows Debugger with Administrator-level permissions, remotely connected to the tablet to manipulate the device's kernel memory. Specifically, the exploit injects a piece of ARM code that switches off the signature checks and briefly diverts the Windows RT kernel to run these instructions.
The RT Jailbreak tool will not permanently alter the machine, but since it is only changing a kernel variable in RAM, it must be run after rebooting or powering up the tablet if one wishes to continue using any unauthorised software.
It may also void the fondleslab's warranty and, while active, obviously allows any ARM-compatible software to run including malware if it even exists.
Microsoft earlier this week brushed off the Rokr exploit but suggested the vulnerability might be closed in a future release of Windows RT.
In fact, the Redmond giant doesn't even consider it to be a security vulnerability. The company stated: We applaud the ingenuity of the folks who worked this out and the hard work they did to document it. Well not guarantee these approaches will be there in future releases.