CVE-2016-3686 in BIG-IP
Summary
by MITRE
The Single Sign-On (SSO) feature in F5 BIG-IP APM 11.x before 11.6.0 HF6 and BIG-IP Edge Gateway 11.0.0 through 11.3.0 might allow remote attackers to obtain sensitive SessionId information by leveraging access to the Location HTTP header in a redirect.
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Analysis
by VulDB Data Team • 07/24/2022
The vulnerability described in CVE-2016-3686 affects the Single Sign-On functionality within F5 BIG-IP APM and Edge Gateway products, specifically targeting versions prior to the mentioned security patches. This issue represents a significant security flaw that could potentially compromise user session integrity and enable unauthorized access to sensitive session information. The vulnerability stems from improper handling of session identifiers within the redirect mechanisms of the SSO implementation, creating an avenue for attackers to exploit the system's response to authentication redirects.
The technical flaw manifests in how the system processes and transmits session identifiers during redirect operations. When users are redirected following authentication attempts, the Location HTTP header contains sensitive SessionId information that should remain protected from unauthorized access. Attackers can leverage their access to this header to extract session tokens that would normally be restricted, effectively undermining the security controls designed to protect user sessions. This weakness directly relates to CWE-200, which addresses the exposure of sensitive information to an unauthorized actor, and represents a clear violation of secure session management principles.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables attackers to potentially hijack user sessions and gain unauthorized access to protected resources. An attacker who successfully exploits this vulnerability can obtain valid SessionId tokens that allow them to impersonate legitimate users and access sensitive applications and data. This threat scenario aligns with ATT&CK technique T1566, which covers credential harvesting through social engineering and network-based attacks. The vulnerability particularly affects organizations relying on F5 BIG-IP for access management, as it undermines the fundamental security assumptions of the SSO implementation and could lead to widespread unauthorized access across multiple applications.
Mitigation strategies for this vulnerability require immediate implementation of the vendor-provided security patches, specifically targeting the affected versions of F5 BIG-IP APM and Edge Gateway. Organizations should also implement network monitoring to detect unauthorized access to Location headers containing session information and establish proper access controls around redirect mechanisms. Additional defensive measures include implementing proper session token management practices, ensuring that session identifiers are not exposed in HTTP headers, and conducting regular security assessments of authentication and authorization mechanisms. The vulnerability underscores the critical importance of proper session management in web applications and highlights the need for comprehensive security testing of authentication flows to prevent similar issues from occurring in other systems.