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[lordvader129]

QUOTE

However, what if the xbe was replaced with a backwards compatable xbe.

the reason the backup of the demo would run was because the demo had no media check, a backward compatible game xbe would have a media check, and wont run

QUOTE

Or would replacing/modding the demo xbe allow for some form of backdoor?

doubtful replacing other files would work, the demo xbe is only designed to perform a few very specific tasks, and thats all it will do

modding the xbe wont work either, any alteration to the code will invalidate the signature and it wont run



xbes and xexs without media checks are an obvious point of exploit, but if its obvious to us it was obvious to MS, and they took extra steps to prevent any exploits, and for once it seems like they did seal everything up tight

[sili]

QUOTE(lordvader129 @ Nov 28 2005, 05:25 PM)

modding the xbe wont work either, any alteration to the code will invalidate the signature and it wont run

If I remember correctly, wasnt SHA bypassed by some guys at a uni in china by padding the file until the signature matched? Im with you in saying that i doubt M$ will allow backward compatibility on files that dont have a mediacheck on them like the hulk demo, but this still could possibly be an avenue