CVE-2018-0486 in XMLTooling-C
Summary
by MITRE
Shibboleth XMLTooling-C before 1.6.3, as used in Shibboleth Service Provider before 2.6.0 on Windows and other products, mishandles digital signatures of user attribute data, which allows remote attackers to obtain sensitive information or conduct impersonation attacks via a crafted DTD.
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Analysis
by VulDB Data Team • 01/20/2023
The vulnerability identified as CVE-2018-0486 represents a critical security flaw in the XMLTooling-C library component that forms part of the Shibboleth identity management system. This issue affects Shibboleth Service Provider versions prior to 2.6.0 on Windows platforms and other products utilizing the affected XMLTooling-C library. The vulnerability stems from improper handling of digital signatures within user attribute data, creating a significant attack surface that adversaries can exploit to compromise system integrity and user confidentiality.
The technical flaw manifests in the library's insufficient validation of digital signatures when processing user attribute information. Specifically, the XMLTooling-C component fails to properly verify the authenticity and integrity of digital signatures associated with attribute data, allowing attackers to manipulate or forge signature validation results. This weakness is particularly dangerous because it occurs during the attribute processing phase of the Shibboleth authentication flow, where user identity and attribute information are critical for access control decisions. The vulnerability is exacerbated by the library's improper handling of Document Type Definitions (DTDs), which can be crafted by attackers to bypass signature validation mechanisms entirely.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass full impersonation capabilities. Remote attackers can leverage this flaw to inject malicious attribute data that appears authentic to the relying party systems, effectively enabling them to assume the identity of legitimate users or gain unauthorized access to protected resources. This represents a severe compromise of the authentication and authorization mechanisms that Shibboleth is designed to protect. The vulnerability affects organizations relying on Shibboleth for single sign-on operations, potentially allowing attackers to escalate privileges, access sensitive applications, or conduct prolonged surveillance of user activities.
Security professionals should implement immediate mitigations including upgrading to Shibboleth Service Provider version 2.6.0 or later, which includes the patched XMLTooling-C library. Organizations should also review their Shibboleth configurations to ensure proper signature validation is enforced and consider implementing additional monitoring for suspicious attribute data patterns. The vulnerability aligns with CWE-347, which addresses improper verification of cryptographic signatures, and maps to ATT&CK technique T1552.001, focusing on credentials from password storage modules. Additionally, organizations should conduct thorough security assessments of their identity infrastructure and consider implementing signature validation monitoring to detect potential exploitation attempts.