Google Analytics By Yoast Premium 5.4.4 Cross Site Scripting
Posted on 13 August 2015
Details ================ Software: Google Analytics by Yoast Premium Version: 5.4.4 Homepage: https://yoast.com/wordpress/plugins/google-analytics/ Advisory report: https://security.dxw.com/advisories/xss-in-google-analytics-by-yoast-premium-by-privileged-users/ CVE: Awaiting assignment CVSS: 5.5 (Medium; AV:N/AC:L/Au:S/C:P/I:P/A:N) Description ================ Stored XSS in Google Analytics by Yoast Premium allows privileged users to attack other users Vulnerability ================ A user with the “manage_options” capability but not the “unfiltered_html” capability is able to add arbitrary JavaScript to a page visible to admins. In the default configuration of WordPress, all users with the “manage_options” capability have the “unfiltered_html” capability. However it is possible to remove the “unfiltered_html” capability from (non-super) admin users. Therefore this presents a vulnerability in which an authenticated user is able to exceed their privileges. Proof of concept ================ Remove the “unfiltered_html” capability from the admin role and log in as a non-super admin For testing you can remove that capability from all users with this line: add_filter(‘user_has_cap‘, function ($allcaps, $cap, $args) { $allcaps[‘unfiltered_html‘] = false; return $allcaps; }, 10, 3); Visit Analytics > Settings Click the Advanced tab Enter the following into the Subdomain tracking field (including the quotes): ” onfocus=”alert(1) Click Save changes Refresh the page Click the Advanced tab Focus the Subdomain tracking field by clicking it or tabbing to it alert(1) will be called Mitigations ================ Upgrade to version 5.4.5 or later. If all users have the ‘unfiltered_html’ capability, or there is only one admin, then there is no issue. Disclosure policy ================ dxw believes in responsible disclosure. Your attention is drawn to our disclosure policy: https://security.dxw.com/disclosure/ Please contact us on security@dxw.com to acknowledge this report if you received it via a third party (for example, plugins@wordpress.org) as they generally cannot communicate with us on your behalf. This vulnerability will be published if we do not receive a response to this report with 14 days. Timeline ================ 2015-07-21: Discovered 2015-07-22: Reported to vendor via email 2015-07-22: Requested CVE 2015-08-10: Vendor confirmed fixed in version 5.4.5 2015-08-10: Published Discovered by dxw: ================ Tom Adams Please visit security.dxw.com for more information.
