PhpBB ImageMagick Path POP Chain Remote Code Execution

This strike emulates a remote code execution via a POP chain attack on PhpBB forum platform. The vulnerability resides in calling the "file_exists" function with user supplied data when checking the ImageMagick binary path. An authenticated attacker may gain arbitrary code execution by uploading a polyglot JPEG-PHAR file beforehand then setting the ImageMagick path to the polyglot, using the "phar://" prefix.