Introduction
Attackers have gained the ability to escalate privileges from basic subscriber accounts to full administrative control on over 400000 WordPress sites due to a critical flaw in the Post SMTP plugin. This vulnerability, tracked as CVE-2025-24000, directly impacts the integrity of password resets and email log confidentiality, exposing a broad swath of the WordPress ecosystem to potential account takeovers and data breaches.
Post SMTP is a widely used WordPress plugin developed by WPExperts, providing advanced SMTP email delivery and logging for WordPress sites. With over 400000 active installations, it is a core component for many organizations' web communication infrastructure. The plugin's REST API endpoints are central to its email logging and management features, but a flaw in their access control implementation has resulted in a significant authentication bypass risk.
Technical Information
CVE-2025-24000 is rooted in the implementation of the get_logs_permission function within the REST API of the Post SMTP plugin. In all versions up to and including 3.2.0, this function only checked if a user was authenticated using the WordPress is_user_logged_in() function. It did not verify the user's role or capabilities, such as whether the user had administrative privileges. As a result, any logged-in user, including those with the lowest privilege level (Subscriber), could access REST API endpoints intended only for administrators.
The most critical endpoint exposed by this flaw is the email log retrieval functionality. Attackers could register as subscribers on a vulnerable site, authenticate, and then directly access endpoints like /wp-json/post-smtp/v1/get-details to retrieve email logs. These logs include sensitive information such as password reset emails sent to administrative accounts. By intercepting these emails, an attacker could reset the admin password and gain full control over the WordPress site.
The root cause is a misunderstanding of authentication versus authorization. The plugin used authentication status as the sole gatekeeper, rather than leveraging WordPress's capability system (such as current_user_can('manage_options')) to enforce proper privilege separation. This oversight resulted in a privilege escalation path that is trivial to exploit and can be automated at scale.
No code snippets are included here as the vulnerable code has only been described in public sources, not published in full.
Patch Information
The developers of the Post SMTP plugin have addressed the security vulnerability by releasing version 3.3.0. This update enhances the access control mechanisms within the plugin's REST API endpoints. Previously, the function get_logs_permission only verified if a user was logged in, without checking their specific privileges. In the patched version, this function has been updated to ensure that only users with appropriate administrative privileges can access sensitive REST API functionalities. This change effectively prevents low-privileged users from intercepting password reset emails and other critical actions, thereby mitigating the risk of unauthorized account takeovers. Site administrators are strongly advised to upgrade to version 3.3.0 or later to secure their WordPress installations.
Reference: securityonline.info
Detection Methods
Detecting unauthorized access to email logs in the Post SMTP plugin involves monitoring for specific indicators of compromise (IoCs) and implementing proactive monitoring strategies. (patchstack.com)
Indicators of Compromise (IoCs):
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Unusual Access Patterns:
- Subscriber-Level Access to Email Logs:
- Indicator: Instances where users with 'Subscriber' roles access or attempt to access email logs.
- Detection Method: Review access logs for entries showing 'Subscriber' users accessing
/wp-json/post-smtp/v1/get-detailsor similar REST API endpoints related to email logs.
- Subscriber-Level Access to Email Logs:
-
Unexpected Password Reset Requests:
- Indicator: Multiple password reset emails sent in a short timeframe, especially if initiated by low-privileged users.
- Detection Method: Monitor email logs for a surge in password reset emails and cross-reference with user roles initiating these requests.
Monitoring Strategies:
-
Audit REST API Access:
- Implementation: Enable detailed logging for REST API requests to capture user roles, accessed endpoints, and timestamps.
- Purpose: Identify unauthorized attempts by low-privileged users to access sensitive endpoints.
-
Set Up Alerts for Anomalous Activities:
- Implementation: Configure alerts for:
- Access to email logs by non-administrative users.
- Multiple password reset requests within a short period.
- Purpose: Promptly detect and respond to potential exploitation attempts.
- Implementation: Configure alerts for:
By focusing on these detection methods and monitoring strategies, administrators can effectively identify and mitigate unauthorized access attempts to email logs, thereby preventing potential account takeovers.
Reference: patchstack.com
Affected Systems and Versions
- Product: Post SMTP WordPress plugin
- Affected versions: All versions up to and including 3.2.0
- Vulnerable configurations: Any WordPress site with Post SMTP plugin version 3.2.0 or below installed and activated
Vendor Security History
WPExperts, the vendor behind Post SMTP, has previously addressed multiple security issues in this plugin. Notably, authorization bypass and stored cross-site scripting vulnerabilities were reported and patched in early 2024. These recurring issues indicate a pattern of access control weaknesses. However, the vendor has shown a reasonable response time, typically releasing patches within weeks of disclosure.