CVE-2014-4172 in Java CAS Client
Summary
by MITRE
A URL parameter injection vulnerability was found in the back-channel ticket validation step of the CAS protocol in Jasig Java CAS Client before 3.3.2, .NET CAS Client before 1.0.2, and phpCAS before 1.3.3 that allow remote attackers to inject arbitrary web script or HTML via the (1) service parameter to validation/AbstractUrlBasedTicketValidator.java or (2) pgtUrl parameter to validation/Cas20ServiceTicketValidator.java.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 12/16/2024
The vulnerability described in CVE-2014-4172 represents a critical security flaw in the Central Authentication Service protocol implementation across multiple client libraries. This issue specifically targets the back-channel ticket validation mechanism that is fundamental to single sign-on operations in enterprise environments. The vulnerability exists in Jasig Java CAS Client versions prior to 3.3.2, .NET CAS Client versions prior to 1.0.2, and phpCAS versions prior to 1.3.3, affecting organizations that rely on centralized authentication systems for their web applications. The flaw allows attackers to manipulate URL parameters during the authentication validation process, potentially leading to unauthorized access and data breaches.
The technical root cause of this vulnerability lies in insufficient input validation within the ticket validation components of the CAS protocol implementation. When the service parameter is passed to validation/AbstractUrlBasedTicketValidator.java or the pgtUrl parameter is processed by validation/Cas20ServiceTicketValidator.java, the applications fail to properly sanitize or validate user-supplied input. This lack of proper input sanitization creates an injection vector that enables attackers to inject malicious web scripts or HTML code directly into the validation process. The vulnerability manifests as a classic parameter injection flaw that can be exploited through manipulation of URL parameters during authentication flows, making it particularly dangerous in environments where authentication tokens are passed through web requests.
The operational impact of this vulnerability extends beyond simple cross-site scripting attacks, as it can enable more sophisticated exploitation techniques within the CAS authentication framework. Attackers can leverage this vulnerability to manipulate the authentication process itself, potentially redirecting users to malicious sites, stealing session tokens, or bypassing authentication mechanisms entirely. The vulnerability affects the core validation logic of the CAS protocol, which means that successful exploitation could compromise the entire single sign-on infrastructure of affected organizations. This creates a significant risk for enterprises that depend on CAS for securing access to multiple applications and services, as a single compromised validation endpoint could potentially allow attackers to gain access to numerous systems.
Organizations should prioritize immediate remediation of this vulnerability by upgrading to the patched versions of the affected CAS client libraries. The recommended mitigation strategy involves implementing comprehensive input validation and sanitization measures across all authentication endpoints, particularly those handling service and pgtUrl parameters. Security teams should also consider implementing additional monitoring and logging of authentication validation requests to detect potential exploitation attempts. From a cybersecurity framework perspective, this vulnerability aligns with CWE-79 (Cross-site Scripting) and CWE-20 (Improper Input Validation) categories, while the exploitation techniques may map to ATT&CK tactics including T1566 (Phishing) and T1071 (Application Layer Protocol) for initial compromise and lateral movement. Organizations should also review their authentication infrastructure for similar input validation weaknesses and implement proper parameter encoding to prevent similar vulnerabilities in other components of their security architecture.