CVE-2023-4035 in Simple Blog Card Plugin
Summary
by MITRE • 08/30/2023
The Simple Blog Card WordPress plugin before 1.31 does not validate and escape some of its shortcode attributes before outputting them back in a page/post where the shortcode 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 • 04/24/2025
The vulnerability identified as CVE-2023-4035 affects the Simple Blog Card WordPress plugin version 1.30 and earlier, representing a critical security flaw that enables stored cross-site scripting attacks through improper input validation and output escaping mechanisms. This issue specifically targets the plugin's shortcode functionality where user-supplied attributes are not adequately sanitized before being rendered back to the page, creating an attack vector that can be exploited by users with contributor privileges and higher. The vulnerability stems from the plugin's failure to implement proper sanitization protocols for shortcode parameters, which directly violates fundamental web security principles and industry standards such as those outlined in CWE-79 - Improper Neutralization of Input During Web Page Generation.
The technical exploitation of this vulnerability occurs when a contributor or higher-privileged user inserts malicious JavaScript code through shortcode attributes within blog posts or pages. When other users view these pages, the stored malicious scripts execute in their browsers, potentially leading to session hijacking, credential theft, or redirection to malicious sites. The flaw exists because the plugin does not employ proper output escaping mechanisms before rendering shortcode attributes back to the HTML document, allowing attackers to inject persistent malicious code that remains stored within the WordPress database. This type of vulnerability falls under the ATT&CK framework category of T1059.001 - Command and Scripting Interpreter: JavaScript, as it leverages JavaScript execution within the browser context. The security implications extend beyond simple XSS, as the attacker can leverage the contributor role to establish persistent malicious payloads that can be triggered whenever the affected pages are accessed.
The operational impact of CVE-2023-4035 is significant for WordPress installations using the vulnerable plugin, as it provides attackers with a method to compromise user sessions and potentially escalate privileges within the WordPress environment. The vulnerability affects not only the immediate execution of malicious scripts but also creates potential for broader compromise through session manipulation and credential harvesting. Organizations running affected versions of the Simple Blog Card plugin face risks of data breaches, unauthorized content modification, and potential lateral movement within their WordPress infrastructure. The stored nature of the XSS attack means that the malicious code persists even after the initial injection, making it particularly dangerous as it can affect multiple users over extended periods. The vulnerability also represents a failure in the principle of least privilege, as it allows users with relatively low privileges to execute code that could affect the entire site's security posture, violating security best practices outlined in various compliance frameworks and security standards.
Mitigation strategies for CVE-2023-4035 should include immediate patching to version 1.31 or later where the vulnerability has been addressed through proper input validation and output escaping mechanisms. Administrators should also implement additional security measures such as restricting contributor privileges to prevent unauthorized shortcode usage, implementing content security policies to limit script execution, and monitoring for suspicious shortcode usage patterns. The fix implemented by the plugin developers should follow established security practices including proper sanitization of all user inputs and application of output escaping before rendering content back to users. Security teams should also conduct thorough audits of all active WordPress plugins to identify similar vulnerabilities and ensure that proper security controls are in place to prevent future incidents of this nature, aligning with the security requirements defined in various industry standards including those related to secure coding practices and vulnerability management.