An CRSF-to-stored-XSS security bug plagues 50,000 ‘Contact Form 7’ Style users.
The latest WordPress plugin security vulnerability is a cross-site request forgery (CSRF) to stored cross-site scripting (XSS) problem in Contact Form 7 Style, which is an add-on to the well-known Contact Form 7 umbrella plugin. It ranks 8.8 out of 10 on the CVSS vulnerability-severity scale (CVE is pending).
Researchers at Wordfence said that there’s no patch yet available, and versions 3.1.9 and below are affected. WordPress removed the plugin from the WordPress plugin repository on Feb. 1.
Vulnerable Contact Form 7 Style
Contact Form 7 is used to create, as its name suggests, contact forms used by websites. The vulnerable Contact Form 7 Style is an add-on that can be used to add additional bells and whistles to those forms that are made with Contact Form 7.
It does this by allowing users to customize a site’s Cascading Style Sheets (CSS) code, which is used to dictate the appearance of WordPress-based websites. This is where the vulnerability lies, according to Wordfence researchers.
Since the number of installed instances for the plugin is so high, Due to the number of sites affected by this plugin’s closure, we are intentionally providing minimal details about this vulnerability to provide users ample time to find an alternative solution. We may provide additional details later as we continue to monitor the situation.
To exploit the flaw, cyberattackers would need to convince a logged-in administrator to click on a malicious link, which can be done via any of the common social-engineering approaches (i.e., through a fraudulent email or instant message).
Wordfence notified the plugin’s developer about the bug in early December; after receiving no response, the researchers then escalated the issue to the WordPress Plugins team in early January. The WordPress Plugins team also contacted the developer with no response, leading to the disclosure this week.
Because, as with all CSRF vulnerabilities, the bug can only be exploited if an admin user performs an action while authenticated to the vulnerable WordPress site, admins should always be wary when clicking on any links.
“If you feel you must click a link, we recommend using incognito windows when you are unsure about a link or attachment,” according to Wordfence. “This precaution can protect your site from being successfully exploited by this vulnerability along with all other CSRF vulnerabilities.”
In this case, users should also deactivate and remove the Contact Form 7 Style plugin and find a replacement, researchers added, since no patch appears to be forthcoming.
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