CVE-2021-24955 in User Registration, Login Form, User Profile & Membership Plugin
Summary
by MITRE • 12/13/2021
The User Registration, Login Form, User Profile & Membership WordPress plugin before 3.2.3 does not escape the data parameter of the pp_get_forms_by_builder_type AJAX action before outputting it back in an attribute, leading to a Reflected Cross-Site Scripting issue
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Analysis
by VulDB Data Team • 12/16/2021
The vulnerability identified as CVE-2021-24955 affects the User Registration, Login Form, User Profile & Membership WordPress plugin version 3.2.2 and earlier. This issue stems from insufficient input validation and output escaping mechanisms within the plugin's AJAX handling functionality. The vulnerability specifically manifests in the pp_get_forms_by_builder_type AJAX action where user-supplied data parameters are not properly sanitized before being rendered back into HTML attributes. This creates a condition where malicious actors can inject arbitrary JavaScript code through carefully crafted input that gets reflected back to users browsing the affected WordPress site.
The technical flaw represents a classic reflected cross-site scripting vulnerability that operates under CWE-79 which defines the weakness of insufficient output escaping or encoding of data within web applications. When the plugin processes the AJAX request, it accepts a data parameter that contains user-provided content without adequate sanitization. This parameter is then incorporated into HTML attributes without proper escaping, allowing attackers to inject malicious scripts that execute in the context of other users' browsers. The vulnerability is particularly concerning because it leverages the AJAX endpoint which is typically used for legitimate user interactions, making the attack vector more subtle and harder to detect.
The operational impact of this vulnerability extends beyond simple script execution as it can enable various malicious activities including session hijacking, credential theft, and redirection to malicious websites. Attackers can craft specially formatted requests that, when processed by the vulnerable plugin, will inject JavaScript code into the page output. This code can then be executed by other users who visit the affected pages, potentially compromising their sessions and gaining unauthorized access to their accounts. The reflected nature of the vulnerability means that the malicious payload must be delivered through a link or other means to trick users into executing the attack, but once triggered, it can persist in the browser context of the victim.
Mitigation strategies for this vulnerability should focus on immediate patching to version 3.2.3 or later where the escaping issue has been resolved. Administrators should also implement additional security measures such as input validation at multiple layers, including validating and sanitizing all user-supplied data before processing. The implementation of Content Security Policy headers can provide additional protection against script injection attacks by restricting the sources from which scripts can be loaded. Organizations should also monitor their WordPress installations for similar vulnerabilities in other plugins and themes, as this type of issue frequently occurs in user-facing components that handle AJAX requests. Regular security audits and vulnerability scanning should be conducted to identify and remediate similar issues before they can be exploited in the wild. The vulnerability aligns with ATT&CK technique T1213 which covers data from information repositories, particularly in how attackers can exploit web application vulnerabilities to access user data and session information through malicious script execution.