One of the ways we help to improve the security of WordPress plugins, not just for our customers, but for everyone using them, is the proactive monitoring of changes made to plugins in the Plugin Directory to try to catch serious vulnerabilities. That again has lead to us catching a vulnerability of a type that hackers are likely to exploit if they know about it. Since the check used to spot this is also included in our Plugin Security Checker (which  is now accessible through a WordPress plugin of its own), it is another of reminder of how that can help to indicate which plugins are in greater need of security review (for which we do as part of our service as well as separately).

In the plugin Swift Help Desk Support Software Ticketing System (Help Desk & Knowledgebase Software) the value of a cookie is passed through the unserialize() function, which could lead to PHP object injection. That occurs in two shortcodes accessed functions in the plugin. One of them being swift_helpdesk_support_callback(), which is located in the file /sections/shd-shortcodes.php. Some ways into the function it checks if the cookie “sc_lead_scoring” exists and then unserializes its value:

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if (isset($_COOKIE['sc_lead_scoring']) && !empty($_COOKIE['sc_lead_scoring'])) {
	$sc_lead_scoring_cookie = unserialize(stripslashes($_COOKIE['sc_lead_scoring']));

Even if the shortcodes that cause those functions to run are not used on the website, any one logged in to WordPress could access them, like they can shortcodes in general, through WordPress AJAX functionality and the vulnerability is also exploitable that way as well.

We notified the developer of the issue a week ago. We haven’t heard back from them and no new version has been released to fix the issue. In line with our disclosure policy, which is based on the need to provide our customers with information on vulnerabilities on a timely basis, we are now disclosing this vulnerability.

The Plugin Security Checker has flagged other possible issues in the plugin, so those using the plugin may want to have someone do a thorough review of the plugin’s security.

Proof of Concept

With our plugin for testing for PHP object injection installed and activated, set the value of the cookie “sc_lead_scoring” to “O:20:”php_object_injection”:0:{}” and then when you visit a page on the website using the “swift_helpdesk_support” shortcode the message “PHP object injection has occurred.” will be shown.

Timeline

• February 8, 2017 – Developer notified.

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