CVE-2016-5749 in Access Manager
Summary
by MITRE
NetIQ Access Manager 4.1 before 4.1.2 HF 1 and 4.2 before 4.2.2 was parsing incoming SAML requests with external entity resolution enabled, which could lead to local file disclosure via an XML External Entity (XXE) attack.
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Analysis
by VulDB Data Team • 09/11/2020
The vulnerability identified as CVE-2016-5749 affects NetIQ Access Manager versions prior to 4.1.2 HF 1 and 4.2.2, representing a critical security flaw that exposes systems to XML External Entity processing attacks. This vulnerability specifically targets the SAML request parsing functionality within the access management platform, creating a pathway for attackers to exploit the system's handling of external entity references in XML documents. The flaw exists due to the application's default configuration that enables external entity resolution when processing incoming SAML requests, which violates fundamental security principles for XML processing and constitutes a direct violation of CWE-611, which addresses improper restriction of XML external entities. The vulnerability operates through the exploitation of XML External Entity (XXE) attack vectors, where malicious actors can craft specially formatted SAML requests that trigger the application to resolve external entities, potentially leading to unauthorized file access on the server hosting the NetIQ Access Manager.
The technical execution of this vulnerability involves the manipulation of SAML request parameters to include external entity declarations that reference local files on the target system. When the NetIQ Access Manager processes these requests with external entity resolution enabled, it can be coerced into reading sensitive files from the local filesystem, including configuration files, credential stores, or other system resources that should remain protected. This represents a classic XXE attack pattern that aligns with ATT&CK technique T1213.002, which focuses on data from information repositories, particularly in scenarios involving XML external entity processing. The vulnerability's impact extends beyond simple information disclosure, as it can potentially expose sensitive authentication data, system configurations, or other confidential information that could be leveraged for further exploitation within the network environment. The attack surface is particularly concerning because SAML requests are typically processed as part of legitimate authentication workflows, making the exploitation less detectable by standard security monitoring systems.
The operational impact of CVE-2016-5749 is significant for organizations relying on NetIQ Access Manager for identity and access management services. Successful exploitation can result in unauthorized access to sensitive system information, potentially leading to privilege escalation, account compromise, or complete system infiltration depending on the files accessed. The vulnerability affects organizations that have not yet applied the necessary patches, particularly those with legacy systems that may not have been upgraded to the patched versions. Security teams face the challenge of identifying and mitigating this vulnerability while maintaining service availability, as disabling external entity resolution could potentially break legitimate SAML functionality. The risk is compounded by the fact that this vulnerability can be exploited remotely without requiring authentication, making it particularly dangerous in environments where the NetIQ Access Manager is exposed to untrusted networks or where attackers can intercept SAML requests during transit. Organizations should consider this vulnerability in the context of broader security frameworks, as it represents a failure to implement proper XML processing security controls that are fundamental to preventing information leakage through external entity references.
Mitigation strategies for CVE-2016-5749 should prioritize the immediate application of the vendor-provided patches for NetIQ Access Manager versions 4.1.2 HF 1 and 4.2.2, which address the root cause by disabling external entity resolution in SAML request processing. Security administrators should also implement network-level controls to monitor and restrict SAML request traffic, particularly when these requests are processed by systems that are not directly exposed to untrusted networks. Additional protective measures include configuring XML parsers to operate in restricted mode, disabling DTD processing, and implementing proper input validation for all SAML request parameters. The vulnerability highlights the importance of applying security patches promptly and maintaining up-to-date security configurations, as the flaw exists in the application's default behavior rather than being a configuration issue that could be remediated through administrative changes. Organizations should also conduct thorough security assessments of their identity and access management systems to identify similar vulnerabilities in other components that may be processing external XML data, ensuring that the principles of secure XML processing are consistently applied across all systems handling such data.