You can do that or something similarly bad in pretty much any language if you have write access to where the files are. That's really a server misconfiguration problem, not php problem.

Huge misfortune of php is that because of the timing and huge popularity in relatively early days of web it got to be permanently associated with amateurs doing stupid shit. I was part of that early era, so trust me that php4 as bad as it was, was still fantastic compared to writing CGI scripts in C, or running mod_perl that you had to restart every time you edit some file.

f-that... read-only containers for the win.