I was thinking more along the lines of "remote shell" tools, to be honest. There are a few php ones that are notorious.
There sure are. I have to resort to things like
"suhosin.executor.func.blacklist = passthru, show_source, shell_exec, system, pcntl_exec, popen, pclose, proc_open, proc_nice, proc_terminate, proc_get_status, proc_close, leak, apache_child_terminate, posix_kill, posix_mkfifo, posix_setpgid, posix_setsid, posix_setuid, escapeshellcmd, escapeshellarg"
for some users due to their inability to write safe code :/ and things like chroot/per user php processes etc.