CVE-2016-10097 in Access Management
Summary
by MITRE
XML External Entity (XXE) Vulnerability in /SSOPOST/metaAlias/%realm%/idpv2 in OpenAM - Access Management 10.1.0 allows remote attackers to read arbitrary files via the SAMLRequest parameter.
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Analysis
by VulDB Data Team • 07/26/2019
The CVE-2016-10097 vulnerability represents a critical XML External Entity processing flaw within the OpenAM access management system version 10.1.0. This vulnerability specifically affects the SSOPOST endpoint with the metaAlias path structure, where the application fails to properly validate and sanitize XML input parameters. The flaw exists in the handling of SAMLRequest parameters that are processed through the idpv2 endpoint, creating an attack surface where malicious actors can exploit the system's XML parser to access arbitrary files on the server. The vulnerability stems from the application's improper configuration of XML parsers that allow external entity resolution without adequate restrictions, enabling attackers to manipulate the XML processing behavior through crafted input.
The technical exploitation of this vulnerability occurs when an attacker submits a malicious SAMLRequest parameter containing external entity declarations that reference local files on the target system. The XML parser within OpenAM processes these external entities and attempts to resolve them, effectively allowing file disclosure attacks against the underlying operating system. This type of vulnerability is classified as CWE-611 according to the Common Weakness Enumeration catalog, which specifically addresses XML external entity processing vulnerabilities that can lead to information disclosure, denial of service, and potentially remote code execution. The attack vector operates through the SSOPOST endpoint where the application expects SAML protocol messages but instead receives maliciously crafted XML that triggers the vulnerable XML parsing mechanism.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially enable attackers to access sensitive system files, configuration data, and credentials stored on the OpenAM server. The vulnerability affects the authentication and authorization processes within the identity management system, potentially compromising the entire single sign-on infrastructure. Attackers could extract database connection strings, encryption keys, user credentials, and other sensitive information that could be used for further exploitation or lateral movement within the network. This vulnerability directly impacts the confidentiality and integrity of the identity management system, as it allows unauthorized access to critical system resources through the SAML authentication flow that is typically considered secure.
Mitigation strategies for CVE-2016-10097 should focus on implementing proper XML parser configuration that disables external entity resolution and DTD processing. Organizations should update to patched versions of OpenAM 10.1.0 or apply the vendor-provided security patches immediately. The implementation of input validation and sanitization measures for all XML parameters, particularly those used in SAML exchanges, is essential. Security configurations should enforce strict XML parser settings that prevent resolution of external entities and references. Network segmentation and monitoring of SSOPOST endpoint traffic can help detect potential exploitation attempts. Additionally, implementing proper access controls and authentication measures for the metaAlias endpoint can limit the attack surface. The vulnerability demonstrates the importance of following secure coding practices and adhering to the principle of least privilege in identity management systems, as outlined in the ATT&CK framework's privilege escalation and credential access techniques that leverage XML parsing vulnerabilities. Organizations should also consider implementing web application firewalls and XML validation rules to prevent such attacks from reaching the vulnerable application components.