Compared with 萌新web10, the condition of the function if() is inverse that means we cannot use those three functions.

To execute shell commands, we can utilize another function which is passthru().

 

ICYMI, the notation ';' is necessary.

 

 The FLAG is still in config.php.

 BTW, maybe you find something different about firefox, cuz I have changed to Kali Linux from MacOS.