CVE-2006-6572 in Access Gateway
Summary
by MITRE
Unspecified vulnerability in Citrix Advanced Access Control (AAC) Option 4.0, and Access Gateway 4.2 with Advanced Access Control 4.2, before 20061114, when the Browser-Only access feature is enabled, allows remote authenticated users to bypass access policies via a certain login method, a different issue than CVE-2006-4846. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 10/01/2017
The vulnerability identified as CVE-2006-6572 represents a critical access control flaw within Citrix Advanced Access Control systems that affects specific versions of the Citrix Access Gateway and Advanced Access Control Option. This security weakness specifically manifests when the Browser-Only access feature is enabled, creating a pathway for remote authenticated attackers to circumvent established access policies. The vulnerability operates independently from CVE-2006-4846, indicating a distinct attack vector that requires separate mitigation strategies. The affected configurations include Citrix Advanced Access Control Option 4.0 and Access Gateway 4.2 with Advanced Access Control 4.2, with the vulnerability remaining unpatched until the release date of November 14, 2006.
The technical exploitation of this vulnerability stems from improper authentication and authorization handling within the Browser-Only access method implementation. When users authenticate through the affected system with Browser-Only access enabled, the authentication process fails to properly validate or enforce access control policies that should normally restrict user access based on predefined security rules. This flaw allows authenticated users to bypass the normal access control mechanisms that would typically prevent them from accessing specific resources or services. The vulnerability essentially creates a backdoor within the authentication flow that enables privilege escalation or unauthorized access to protected resources, representing a significant deviation from expected security behavior.
From an operational impact perspective, this vulnerability poses substantial risk to organizations relying on Citrix Access Gateway for secure remote access solutions. The ability for remote authenticated users to bypass access policies means that legitimate users who have successfully authenticated can potentially access systems, applications, or data they should not have authorization to reach. This could lead to data breaches, unauthorized system modifications, or privilege escalation attacks that compromise the integrity and confidentiality of sensitive information. The vulnerability's remote nature means attackers do not need physical access to the network and can exploit it from external locations, making it particularly dangerous for organizations with remote workforce capabilities. Organizations using this specific Citrix configuration may experience unauthorized access incidents that could result in regulatory compliance violations and significant financial losses.
Security mitigations for this vulnerability should focus on immediate patch application to versions released after November 14, 2006, which would contain the necessary fixes for the authentication bypass issue. Organizations should also implement network segmentation and additional access controls to limit the potential impact of exploitation. The mitigation strategy should include disabling the Browser-Only access feature if it is not essential for business operations, as this removes the attack surface associated with the vulnerable functionality. Additionally, implementing comprehensive monitoring and logging of authentication events can help detect suspicious access patterns that might indicate exploitation attempts. This vulnerability aligns with CWE-284, which addresses improper access control, and may map to ATT&CK techniques involving privilege escalation and lateral movement through compromised authentication mechanisms. Organizations should conduct thorough security assessments of their Citrix implementations to identify similar vulnerabilities and ensure proper access control enforcement throughout their network infrastructure.