CVE-2019-12346 in SAML SP Single Sign On plugin
Summary
by MITRE
In the miniOrange SAML SP Single Sign On plugin before 4.8.73 for WordPress, the SAML Login Endpoint is vulnerable to XSS via a specially crafted SAMLResponse XML post.
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Analysis
by VulDB Data Team • 10/07/2023
The vulnerability identified as CVE-2019-12346 affects the miniOrange SAML SP Single Sign On plugin for WordPress, specifically versions prior to 4.8.73. This issue represents a cross-site scripting vulnerability that occurs within the SAML Login Endpoint functionality, which serves as a critical authentication mechanism for single sign-on operations. The vulnerability stems from insufficient input validation and output encoding within the plugin's handling of SAMLResponse XML data, creating a pathway for malicious actors to inject arbitrary script code into the authentication flow.
The technical flaw manifests when the plugin processes SAMLResponse XML data submitted through HTTP POST requests to the SAML Login Endpoint. The vulnerability arises because the plugin fails to properly sanitize or encode user-supplied SAMLResponse content before rendering it in the web application context. This improper handling allows attackers to craft malicious SAMLResponse XML payloads containing script tags or other XSS vectors that can execute within the victim's browser context when the response is processed. The vulnerability is classified as a classic reflected cross-site scripting issue where the malicious content originates from the SAMLResponse itself rather than from server-side stored data.
The operational impact of this vulnerability extends beyond typical XSS consequences, as it specifically targets the authentication infrastructure of WordPress sites using SAML single sign-on. An attacker who successfully exploits this vulnerability could potentially steal session cookies, perform unauthorized actions on behalf of authenticated users, or redirect users to malicious websites. Given that the plugin facilitates enterprise-level authentication, the attack surface includes privileged users who may have elevated access rights within the WordPress environment. The vulnerability could enable attackers to escalate privileges, access sensitive administrative functions, or compromise the entire WordPress installation through session hijacking or credential theft.
Mitigation strategies for this vulnerability require immediate patching of the miniOrange plugin to version 4.8.73 or later, which implements proper input sanitization and output encoding for SAMLResponse data. Organizations should also implement additional security controls such as content security policies to limit script execution, monitor authentication endpoints for suspicious activity, and validate all SAMLResponse content through proper XML schema validation. The vulnerability aligns with CWE-79 - Improper Neutralization of Input During Web Page Generation, and represents a specific implementation weakness in the plugin's security controls. From an attack framework perspective, this vulnerability would be categorized under the credential access and privilege escalation domains of the MITRE ATT&CK framework, potentially enabling adversaries to establish persistent access through stolen session tokens or compromised authentication flows.
Security practitioners should also consider implementing network-level protections such as web application firewalls to detect and block malicious SAMLResponse payloads, while maintaining comprehensive logging of authentication events for forensic analysis. Regular security assessments of third-party WordPress plugins remain essential for identifying similar vulnerabilities in the broader ecosystem. The vulnerability demonstrates the critical importance of validating and sanitizing all user-supplied data within authentication mechanisms, particularly when handling standardized protocols like SAML that may carry complex XML structures. Organizations using SAML-based authentication should also review their overall security posture and ensure proper input validation across all authentication endpoints to prevent similar issues in other components of their security infrastructure.