Kaltura Remote PHP Code Execution over Cookie

This module exploits an Object Injection vulnerability in Kaltura.
By exploiting this vulnerability, unauthenticated users can execute
arbitrary code under the context of the web server user.

Kaltura makes use of a hardcoded cookie secret which allows to sign
arbitrary cookie data. After passing this signature check, the base64-
decoded data is passed to PHPs unserialize() function which allows for
code execution. The constructed object is again based on the SektionEins
Zend code execution POP chain PoC. Kaltura versions prior to 13.1.0 are
affected by this issue.

A valid entry_id (which is required for this exploit) can be obtained
from any media resource published on the kaltura installation.

This module was tested against Kaltura 13.1.0-2 installed on Ubuntu 14.04.