Exploit for Joomla 3.4.4 – 3.6.4 CVE-2016-8869 and CVE-2016-8870 with File Upload web shell
While analysing the recent Joomla exploit in com_users:user.register we came across a problem with the upload whitelisting. They don’t allow files containing <?php, or with the extensions .php and .phtml, but they do allow <?= and .pht files, which works out of the box on most hosting environments, including the standard Ubuntu LAMP install, as per:
Choose the username, password and e-mail address to use and point it at the URL for your Joomla website. Use the -x and -s options to customise exploit behaviour, -s searches for the given string in the output after running the PHP file (specified in -x), an example is provided which proves remote code execution.