CVE-2022-1217 in Custom TinyMCE Shortcode Button Plugin
Summary
by MITRE • 05/16/2022
The Custom TinyMCE Shortcode Button WordPress plugin through 1.1 does not sanitise and escape the PHP_SELF variable before outputting it back in an attribute in an admin page, leading to Reflected Cross-Site Scripting.
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Analysis
by VulDB Data Team • 05/18/2022
The vulnerability identified as CVE-2022-1217 affects the Custom TinyMCE Shortcode Button WordPress plugin version 1.1 and earlier, presenting a reflected cross-site scripting flaw that arises from inadequate sanitization of the PHP_SELF variable. This issue occurs within the plugin's administrative interface where user-supplied data is directly incorporated into HTML attributes without proper escaping mechanisms, creating an avenue for malicious actors to inject harmful scripts. The vulnerability specifically manifests when the plugin processes the PHP_SELF variable which contains the path of the current script, and fails to properly sanitize this input before rendering it within HTML attributes, thereby enabling attackers to execute arbitrary JavaScript code in the context of the victim's browser.
The technical exploitation of this vulnerability follows a reflected XSS pattern where an attacker crafts a malicious URL containing crafted script payloads that are then reflected back to the victim's browser through the vulnerable plugin's admin interface. The PHP_SELF variable, which typically contains the script name and path, becomes a vector for injection when the plugin fails to apply proper output escaping before incorporating this data into HTML attributes. This flaw falls under CWE-79 - Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly sanitize user input before including it in web page content. The vulnerability's impact is amplified by the fact that it occurs within the WordPress admin context, potentially allowing attackers to escalate privileges or execute unauthorized actions with elevated permissions.
The operational impact of this vulnerability extends beyond simple script execution as it represents a significant security risk for WordPress administrators who may be tricked into visiting malicious URLs containing the XSS payload. The reflected nature of the vulnerability means that the attack requires user interaction through a specially crafted link, but once executed, the malicious script can perform actions such as stealing session cookies, redirecting users to malicious sites, or modifying the administrative interface. This poses a serious threat to WordPress site integrity and user data protection, particularly in environments where administrators have elevated privileges and access to sensitive content management features. The vulnerability's location within a widely used plugin increases its potential attack surface and impact across numerous WordPress installations.
Mitigation strategies for CVE-2022-1217 should prioritize immediate plugin updates to versions that address the sanitization flaw, as this represents the most direct and effective solution. Administrators should also implement proper input validation and output escaping mechanisms for all user-supplied data, particularly within administrative interfaces. The implementation of Content Security Policy headers can provide additional protection against reflected XSS attacks by restricting script execution and limiting the impact of successful exploitation attempts. Security monitoring should be enhanced to detect suspicious URL patterns and user behavior that may indicate attempts to exploit this vulnerability. Organizations should also consider implementing web application firewalls that can detect and block malicious payloads targeting this specific XSS vector. The vulnerability aligns with ATT&CK technique T1213.002 - Data from Information Repositories, as it enables attackers to potentially access and manipulate administrative functions through browser-based exploitation. Regular security audits and vulnerability assessments should be conducted to identify similar sanitization issues within other plugins and themes, ensuring comprehensive protection against cross-site scripting attacks that could compromise WordPress administrative environments and user data integrity.