CVE-2021-24409 in Prismatic Plugin
Summary
by MITRE • 07/13/2021
The Prismatic WordPress plugin before 2.8 does not escape the 'tab' GET parameter before outputting it back in an attribute, leading to a reflected Cross-Site Scripting issue which will be executed in the context of a logged in administrator
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Analysis
by VulDB Data Team • 07/15/2021
The vulnerability identified as CVE-2021-24409 affects the Prismatic WordPress plugin version 2.7 and earlier, representing a critical reflected cross-site scripting flaw that specifically targets authenticated administrators. This vulnerability resides in the plugin's handling of the 'tab' GET parameter within HTTP requests, where insufficient input sanitization allows malicious payloads to be reflected back to users without proper HTML escaping. The issue manifests when administrators navigate to specific plugin interfaces that process this parameter, creating a persistent attack surface that can be exploited by remote attackers to execute arbitrary JavaScript code within the administrator's browser context.
The technical implementation of this vulnerability stems from a failure to properly escape user-supplied input before incorporating it into HTML attributes. When the plugin processes the 'tab' parameter from the URL query string, it directly incorporates this value into HTML output without appropriate sanitization or encoding mechanisms. This represents a classic reflected XSS vulnerability categorized under CWE-79, which occurs when web applications include untrusted data in web pages without proper validation or encoding. The vulnerability specifically impacts the plugin's administrative interface where the tab parameter is used to determine which section of the plugin settings to display, making it particularly dangerous as it can be triggered through simple URL manipulation.
The operational impact of this vulnerability is severe as it enables attackers to execute malicious scripts in the context of logged-in administrators, potentially leading to complete compromise of the WordPress installation. An attacker could craft a malicious URL containing a JavaScript payload that, when clicked by an administrator, would execute within the administrator's browser session. This execution context provides attackers with the ability to perform actions such as modifying plugin settings, accessing sensitive data, creating new administrator accounts, or even installing malware. The vulnerability is particularly dangerous because it requires no special privileges from the attacker beyond the ability to send a malicious link to an administrator, and the reflected nature of the XSS means that the attack is immediately effective upon page load without requiring any additional authentication.
Mitigation strategies for this vulnerability include immediate upgrade to Prismatic plugin version 2.8 or later, which contains the necessary input sanitization fixes. Organizations should also implement additional protective measures such as web application firewalls that can detect and block suspicious parameter values, input validation at the application level, and regular security scanning of WordPress installations. The vulnerability aligns with ATT&CK technique T1566.001 for initial access through spearphishing attachments or links, and T1059.001 for command and scripting interpreter execution. Administrators should also consider implementing Content Security Policy headers to limit script execution capabilities and establish monitoring for unusual parameter values in plugin interfaces. Regular security audits of WordPress plugins and themes remain essential to identify similar vulnerabilities that could compromise system integrity and user data confidentiality.