CVE-2017-14313 in Shibboleth Plugin
Summary
by MITRE
The shibboleth_login_form function in shibboleth.php in the Shibboleth plugin before 1.8 for WordPress is prone to an XSS vulnerability due to improper use of add_query_arg().
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Analysis
by VulDB Data Team • 12/28/2022
The vulnerability identified as CVE-2017-14313 affects the Shibboleth plugin for WordPress, specifically targeting the shibboleth_login_form function within the shibboleth.php file. This issue represents a classic cross-site scripting vulnerability that arises from inadequate input validation and output escaping mechanisms within the plugin's codebase. The vulnerability exists in versions prior to 1.8, indicating that it was a known security flaw that required patching to protect WordPress installations using the Shibboleth authentication plugin.
The technical flaw manifests through the improper utilization of WordPress's add_query_arg() function, which is designed to safely construct URLs by properly encoding query parameters. When developers fail to adequately escape or sanitize user-supplied input before incorporating it into URL parameters, malicious actors can inject malicious scripts that execute in the context of other users' browsers. This particular implementation flaw allows attackers to manipulate URL parameters that are subsequently processed by the shibboleth_login_form function, creating opportunities for persistent cross-site scripting attacks.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to steal session cookies, perform unauthorized actions on behalf of authenticated users, or redirect victims to malicious websites. Given that the Shibboleth plugin typically handles authentication flows and user sessions, successful exploitation could compromise the entire authentication system. The vulnerability affects WordPress installations that rely on Shibboleth for single sign-on functionality, potentially exposing organizations to credential theft and unauthorized access to sensitive resources that depend on Shibboleth authentication.
Security professionals should note that this vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications, and represents a common pattern where input validation fails to properly sanitize user-supplied data before it is rendered in web responses. The ATT&CK framework categorizes this as a technique for code injection, specifically targeting web application vulnerabilities that allow adversaries to execute malicious code in user browsers. Organizations using the affected plugin versions should immediately implement the available patch from the plugin developers and conduct security assessments to ensure no exploitation has occurred. The vulnerability demonstrates the critical importance of proper input sanitization and output escaping in web applications, particularly in authentication-related code where the stakes for security breaches are exceptionally high.