The article states:

>"Somewhere in the Linux operating system, which runs in many servers, is code that authorizes a user by verifying a typed password against a stored encrypted one. An implanted chip can alter part of that code so the server won’t check for a password—and presto! A secure machine is open to any and all users."

I realize the intended audience for this article is not a technical crowd but can someone walk me through in practical terms how such a chip might subvert the /bin/login binary?