Block an application's read/write access to a specific file in OS X?
You could just use the built-in sandboxing features of Mac OS X.

Create a custom profile that limits access to the SystemVersion.plist file, using syntax like this:

(version 1)
(deny file* (literal "/System/Library/CoreServices/SystemVersion.plist"))
(allow default)


Save that as for example ~/myprofile.sb and then run your program like this:

sandbox-exec -f ~/myprofile.sb "/Application/My Program.app/Contents/MacOS/My Program"