If there was a race as to which console get an exploit first, the Xbox 360 now gets the dubious honor of having the first publically available exploit usable by anyone who manages to jump all the hurdles while creating a proof-of-concept.

In case people don't know, the 360 has a hypervisor which basically keeps all the running software in check, making sure that it's all signed. If you're Microsoft, one of the biggest advantages of a hypervisor is that it doesn't allow hackers to use buffer overflows for exploits.

These buffer overflows have been the bane for Sony on the PSP. Anyone who owns a PSP would know that practically all the exploits have been using a buffer overflow to get their unsigned code to run.

Some anonymous hackers have succeeded in getting unsigned code to run by exploiting the hypervisor, allowing it to run unsigned, unencrypted code. While the hack details itself are pretty technical, here are a few things which I'm sure everyone will understand:

Systems Affected: All Xbox 360 systems with a kernel version of 4532 (released Oct 31, 2006) and 4548 (released Nov 30, 2006). Versions prior to 4532 are not affected. Bug was fixed in version 4552.

We have discovered a vulnerability in the Xbox 360 hypervisor that allows privilege escalation into hypervisor mode. Together with a method to inject data into non-privileged memory areas, this vulnerability allows an attacker with physical access to an Xbox 360 to run arbitrary code such as alternative operating systems with full privileges and full hardware access.

Unprivileged code interacts with the hypervisor via the "sc" ("syscall") instruction, which causes the machine to enter hypervisor mode. The vulnerability is a result of incomplete checking of the parameters passed to the syscall dispatcher.