Unauthenticated Stored XSS Vulnerability Patched in Ultimate Member WordPress Plugin
On February 28th, 2024, during our second Bug Bounty Extravaganza, we received a submission for an unauthenticated stored Cross-Site Scripting (XSS) vulnerability in Ultimate Member, a WordPress plugin with more than 200,000+ active installations. This vulnerability can be leveraged to inject malicious web scripts.
Props to stealthcopter who discovered and responsibly reported this vulnerability through the Wordfence Bug Bounty Program. This researcher earned a bounty of $563.00 for this discovery during our Bug Bounty Program Extravaganza. Our mission is to Secure the Web, so we are proud to continue investing in vulnerability research like this and collaborating with researchers of this caliber through our Bug Bounty Program. This demonstrates that we are not only committed to investing in making the WordPress ecosystem more secure, but also the entire web.
All Wordfence Premium, Wordfence Care, and Wordfence Response customers, as well as those using the free version of our plugin, are protected against any exploits targeting this vulnerability by the Wordfence firewallâs built-in Cross-Site Scripting protection.
We provided full disclosure details to the Ultimate Member Team on March 2, 2024, and received a response on March 4, 2024. The developer released a patch on March 6, 2024. We would like to commend the Ultimate Member Team for their prompt response and timely patch.
We urge users to update their sites with the latest patched version of Ultimate Member, which is version 2.8.4, as soon as possible.
Vulnerability Summary from Wordfence Intelligence
Description: Ultimate Member $user_id,
âroleâ => um_user( âroleâ ),
âaccount_statusâ => um_user( âaccount_statusâ ),
âaccount_status_nameâ => um_user( âaccount_status_nameâ ),
âcover_photoâ => um_user( âcover_photoâ, $this->cover_size ),
âdisplay_nameâ => um_user( âdisplay_nameâ ),
âprofile_urlâ => um_user_profile_url(),
âcan_editâ => $can_edit,
âedit_profile_urlâ => um_edit_profile_url(),
âavatarâ => get_avatar( $user_id, $this->avatar_size ),
âdisplay_name_htmlâ => um_user( âdisplay_nameâ, âhtmlâ ),
âdropdown_actionsâ => $dropdown_actions,
âhook_just_after_nameâ => preg_replace( â/^s+/imâ, â, $hook_just_after_name ),
âhook_after_user_nameâ => preg_replace( â/^s+/imâ, â, $hook_after_user_name ),
);
The attacker can provide a name with a malicious script during registration as an unauthenticated user.
As always, Cross-Site Scripting vulnerabilities can be used to inject code that can add new administrative users, redirect victims to malicious sites, inject backdoors into theme and plugin files, and so much more. Combined with the fact that the vulnerability can be exploited by attackers with no privileges on a vulnerable site, this means that there is a high chance that unauthenticated attackers could gain administrative user access on sites running the vulnerable version of the plugin when successfully exploited. As such, we strongly recommend that you verify that your site is running the most up to date version of the plugin immediately.
Disclosure Timeline
February 28, 2024 â We receive the submission of the stored Cross-Site Scripting (XSS) vulnerability in Ultimate Member via the Wordfence Bug Bounty Program.
March 1, 2024 â We validate the report and confirm the proof-of-concept exploit.
March 2, 2024 â We send over the full disclosure details.
March 4, 2024 â The vendor acknowledges the report and begins working on a fix.
March 6, 2024 â The fully patched version of the plugin, 2.8.4, is released.
Conclusion
In this blog post, we detailed a stored Cross-Site Scripting (XSS) vulnerability within the Ultimate Member plugin affecting versions 2.8.3 and earlier. This vulnerability allows unauthenticated threat actors to inject malicious web scripts into pages that execute when a user accesses an affected page. The vulnerability has been fully addressed in version 2.8.4 of the plugin.
We encourage WordPress users to verify that their sites are updated to the latest patched version of Ultimate Member.
All Wordfence users, including those running Wordfence Premium, Wordfence Care, and Wordfence Response, as well as sites running the free version of Wordfence, are fully protected against this vulnerability.
If you know someone who uses this plugin on their site, we recommend sharing this advisory with them to ensure their site remains secure, as this vulnerability poses a significant risk.
Source: wordfence.com