The point is that binfmt_misc could allow you to run unstrusted code in a context where you were not expecting to run any code.
For instance, if I do "./budget.pdf", I expect it to run the code from my pdf reader. In this case, an attack would require exploiting a vulnerability in the pdf reader. That is to say, budget.pdf is not untrusted code, but rather untrusted data.
However, in this case the unstrusted data can claim that it is code; in which case it would be executed as such.
In contrast, when I do `evince budget.pdf`, the only way for budget.pdf to become code is to trick the pdf reader into thinking it is code.
Granted, this is largely a moot point as most people would be using a GUI file manager; which already has a common interface for running programs and opening data files; and already automatically determines which action to take.
For instance, if I do "./budget.pdf", I expect it to run the code from my pdf reader. In this case, an attack would require exploiting a vulnerability in the pdf reader. That is to say, budget.pdf is not untrusted code, but rather untrusted data.
However, in this case the unstrusted data can claim that it is code; in which case it would be executed as such.
In contrast, when I do `evince budget.pdf`, the only way for budget.pdf to become code is to trick the pdf reader into thinking it is code.
Granted, this is largely a moot point as most people would be using a GUI file manager; which already has a common interface for running programs and opening data files; and already automatically determines which action to take.