CVE-2024-38684 in SlingBlocks Plugin
Summary
by MITRE • 07/20/2024
Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in FunnelKit SlingBlocks – Gutenberg Blocks by FunnelKit (Formerly WooFunnels) allows Stored XSS.This issue affects SlingBlocks – Gutenberg Blocks by FunnelKit (Formerly WooFunnels): from n/a through 1.4.1.
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Analysis
by VulDB Data Team • 03/17/2025
This vulnerability represents a critical cross-site scripting weakness in the FunnelKit SlingBlocks Gutenberg plugin, which has been identified as a stored XSS flaw affecting versions through 1.4.1. The issue stems from inadequate input sanitization during web page generation processes, where user-supplied data is not properly neutralized before being rendered in web interfaces. This allows attackers to inject malicious scripts that persist in the application's database and execute whenever affected pages are loaded, making it particularly dangerous for content management systems where multiple users interact with the platform. The vulnerability is classified under CWE-79 as improper neutralization of input during web page generation, which directly enables XSS attacks that can compromise user sessions and steal sensitive information.
The technical implementation of this flaw occurs when the plugin processes user inputs through Gutenberg block interfaces without adequate validation or sanitization mechanisms. When administrators or users create content using SlingBlocks, the plugin fails to properly escape or filter potentially malicious input before storing it in the database. This stored data is then retrieved and rendered in subsequent page views, executing the injected scripts in the context of other users' browsers. The vulnerability is particularly concerning because it operates at the web application level, where the attack vector can be triggered simply by viewing affected pages rather than requiring specific user interaction beyond normal browsing behavior. This makes the attack surface extremely broad and difficult to contain.
The operational impact of this stored XSS vulnerability extends beyond simple script execution, potentially enabling complete compromise of user sessions, data theft, and privilege escalation within the affected WordPress environment. Attackers could leverage this vulnerability to steal administrator credentials, modify content, redirect users to malicious sites, or even install backdoors for persistent access to the compromised system. The vulnerability affects the entire WordPress ecosystem where SlingBlocks is installed, potentially impacting thousands of websites that rely on this plugin for funnel creation and page building. Security researchers have noted that this type of vulnerability is particularly dangerous in enterprise environments where multiple administrators and users interact with content management systems, as it can facilitate lateral movement and data exfiltration across the entire platform. The ATT&CK framework categorizes this vulnerability under T1566 as a credential access technique, as it can be used to harvest session cookies and other authentication tokens.
Mitigation strategies for this vulnerability require immediate attention from system administrators, beginning with upgrading to the latest version of the SlingBlocks plugin where the XSS flaw has been addressed. Organizations should implement comprehensive input validation and output encoding mechanisms throughout their web applications, ensuring that all user-generated content is properly sanitized before storage or rendering. Security teams should deploy web application firewalls and content security policies to detect and prevent malicious script injection attempts, while also conducting regular security assessments to identify similar vulnerabilities in other plugins and themes. Additionally, implementing principle of least privilege access controls and regular security monitoring can help detect unauthorized modifications to content or configuration changes that might indicate exploitation attempts. The vulnerability underscores the importance of maintaining up-to-date software and implementing robust security practices throughout the entire application lifecycle to prevent similar issues from occurring in other components of the web infrastructure.