Description

The POST SMTP Mailer WordPress plugin, utilized by 300,000 websites for email delivery, has been found vulnerable to two critical security flaws, potentially allowing attackers to seize complete control over site authentication. Discovered by Wordfence security researchers Ulysses Saicha and Sean Murphy in December 2023, the first vulnerability, tracked as CVE-2023-6875, is a severe authorization bypass flaw resulting from a "type juggling" issue in the connect-app REST endpoint. Exploitable in all plugin versions up to 2.8.7, this flaw enables unauthenticated attackers to reset the API key, gaining access to sensitive log information, including password reset emails. The attacker manipulates a mobile app-related function to set a valid token with a zero value for the authentication key, triggering a password reset for the site's admin. Subsequently, the attacker extracts the key within the application, altering it and locking the legitimate user out. With administrator privileges, the attacker gains full access, allowing the planting of backdoors, modification of plugins and themes, content editing and publishing, or redirection to malicious destinations. The second vulnerability, CVE-2023-7027, is a cross-site scripting (XSS) flaw arising from inadequate input sanitization and output escaping in POST SMTP up to version 2.8.7. This flaw enables attackers to inject arbitrary scripts into affected site web pages. Wordfence notified the vendor on December 8, 2023, and, after submitting the report, provided a proof-of-concept (PoC) exploit on December 15. The vendor addressed both vulnerabilities in version 2.8.8 released on January 1, 2024. Approximately 150,000 sites run vulnerable versions, and even those with version 2.8 and higher may be at risk, with thousands potentially vulnerable based on download statistics since the patch release.