CVE-2023-0374 in W4 Post List Plugin
Summary
by MITRE • 04/17/2023
The W4 Post List WordPress plugin before 2.4.6 does not validate and escape some of its block options before outputting them back in a page/post where the block is embed, which could allow users with the contributor role and above to perform Stored Cross-Site Scripting attacks.
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Analysis
by VulDB Data Team • 05/05/2023
The vulnerability identified as CVE-2023-0374 affects the W4 Post List WordPress plugin version 2.4.5 and earlier, presenting a significant security risk through stored cross-site scripting exploitation. This issue stems from inadequate input validation and output escaping mechanisms within the plugin's block options handling functionality. The vulnerability specifically targets the plugin's ability to process and render block options without proper sanitization, creating an avenue for malicious actors to inject persistent malicious scripts into WordPress pages and posts where these blocks are embedded.
The technical flaw manifests in the plugin's failure to validate and escape user-supplied data within block options before rendering them back to users. When administrators or users with contributor privileges and above create or modify block configurations, the plugin processes these inputs without sufficient sanitization measures. This oversight allows attackers to embed malicious JavaScript code within block options that persists in the database and executes whenever the affected page or post is rendered. The vulnerability is particularly concerning because it affects users with relatively low privilege levels, specifically contributors and above, making it accessible to a broader range of potential attackers within WordPress environments.
From an operational impact perspective, this stored cross-site scripting vulnerability enables attackers to execute malicious code in the contexts of affected WordPress sites. Successful exploitation could result in unauthorized data access, session hijacking, defacement of content, or redirection to malicious websites. The persistent nature of stored XSS means that once the malicious payload is injected, it will continue to execute for all users who view the affected pages until the vulnerability is patched. This creates ongoing security exposure for WordPress installations using the vulnerable plugin version, potentially compromising user sessions and site integrity.
The vulnerability aligns with CWE-79 which describes Cross-Site Scripting flaws in software applications, and represents a classic case of insufficient output escaping in web applications. From an ATT&CK framework perspective, this vulnerability maps to technique T1566.001 for Phishing and T1071.001 for Application Layer Protocol: Web Protocols, as it enables attackers to deliver malicious payloads through web interfaces. The impact extends beyond immediate script execution to potential privilege escalation scenarios where attackers could leverage the XSS to gain deeper access to WordPress administrative functions or extract sensitive information from user sessions. Organizations using the W4 Post List plugin should immediately update to version 2.4.6 or later to mitigate this risk, as the vulnerability provides attackers with a straightforward path to persistent code execution within affected WordPress environments.
This vulnerability demonstrates the critical importance of input validation and output escaping in web applications, particularly within content management systems where user-generated content processing is common. The security implications extend beyond simple script injection to encompass potential data breaches and service disruption. The attack vector requires minimal privileges, making it particularly dangerous as it can be exploited by users who do not necessarily have administrative access but possess contributor-level permissions. Regular security auditing and timely patch management become essential defensive measures against such vulnerabilities, as they represent common entry points for attackers seeking to compromise WordPress installations and their underlying data integrity.