CVE-2023-45646 in PDF Block Plugin
Summary
by MITRE • 10/25/2023
Auth. (contributor+) Stored Cross-Site Scripting (XSS) vulnerability in Henryholtgeerts PDF Block plugin
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Analysis
by VulDB Data Team • 11/03/2023
The CVE-2023-45646 vulnerability represents a critical stored cross-site scripting flaw within the Henryholtgeerts PDF Block plugin for WordPress, affecting users with contributor level permissions or higher. This vulnerability resides in the plugin's handling of user input within PDF embedding functionality, where unfiltered and improperly sanitized data is stored in the database and subsequently executed in subsequent page requests. The issue manifests when contributors or higher-privileged users create or modify content containing malicious script payloads within PDF block parameters, which then persist in the WordPress database and execute whenever the affected pages are rendered to other users.
The technical exploitation of this vulnerability occurs through the manipulation of input fields within the PDF block editor interface, where user-provided content is directly embedded into HTML output without adequate sanitization or encoding mechanisms. This stored XSS vulnerability allows attackers with contributor privileges to inject malicious JavaScript code that executes in the context of other users' browsers, potentially enabling session hijacking, credential theft, or redirection to malicious sites. The vulnerability is particularly concerning as it requires minimal privileges to exploit, making it accessible to users who normally should not have the capability to execute arbitrary code within the WordPress environment.
The operational impact of this vulnerability extends beyond simple script execution, as it can be leveraged for more sophisticated attacks including privilege escalation attempts, data exfiltration, and establishment of persistent backdoors within the WordPress installation. Attackers can craft malicious payloads that exploit the stored XSS to steal cookies, modify content, or redirect users to phishing sites that appear legitimate within the context of the WordPress administration. The vulnerability affects WordPress sites using the Henryholtgeerts PDF Block plugin version 1.0.0 through 1.2.1, where the plugin fails to properly validate and sanitize user input before storing it in the database, creating a persistent threat that remains active until the vulnerability is patched or the malicious content is manually removed.
Mitigation strategies for this vulnerability include immediate patching of the affected plugin to version 1.2.2 or later, which implements proper input sanitization and output encoding mechanisms. Administrators should also implement additional security measures such as role-based access control restrictions, input validation at multiple layers, and regular security audits of installed plugins. The vulnerability aligns with CWE-79 (Cross-Site Scripting) and can be categorized under ATT&CK technique T1059.007 (Command and Scripting Interpreter: JavaScript) as it enables execution of malicious JavaScript code through web interfaces. Organizations should also consider implementing Content Security Policy headers and regular monitoring of user-generated content to detect potential exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation and output encoding in web applications, particularly in plugins that handle user-generated content with elevated privileges.