CVE-2017-4963 in Cloud Foundry
Summary
by MITRE
An issue was discovered in Cloud Foundry Foundation Cloud Foundry release v252 and earlier versions, UAA stand-alone release v2.0.0 - v2.7.4.12 & v3.0.0 - v3.11.0, and UAA bosh release v26 & earlier versions. UAA is vulnerable to session fixation when configured to authenticate against external SAML or OpenID Connect based identity providers.
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Analysis
by VulDB Data Team • 12/29/2019
The vulnerability identified as CVE-2017-4963 represents a critical session management flaw within the Cloud Foundry User Account and Authentication (UAA) system. This issue affects multiple versions of the Cloud Foundry platform and its standalone UAA components, creating a significant security risk for organizations relying on these systems for identity management. The vulnerability specifically manifests when UAA is configured to authenticate users against external identity providers using SAML or OpenID Connect protocols, making it particularly dangerous in enterprise environments where single sign-on functionality is commonly implemented.
The technical flaw stems from improper session handling during the authentication process when external identity providers are involved. When users authenticate through SAML or OpenID Connect identity providers, the UAA system fails to properly invalidate or regenerate session identifiers, allowing attackers to potentially reuse valid session tokens. This session fixation vulnerability occurs because the system does not adequately separate the authentication session from the user session, creating a scenario where an attacker who has obtained a valid session token can maintain access to the system even after legitimate users have authenticated or logged out. The flaw operates at the application layer and affects the session management mechanisms that should ensure unique and secure session identifiers for each authentication event.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it can enable persistent compromise of user accounts and potentially provide attackers with elevated privileges within the Cloud Foundry environment. Attackers exploiting this vulnerability could maintain access to systems even after legitimate users have changed their passwords or logged out, creating a persistent threat vector. The risk is particularly elevated in multi-tenant environments where a compromised session could potentially allow attackers to access resources belonging to other users or organizations within the same Cloud Foundry deployment. This vulnerability also impacts the integrity of the authentication process, undermining the trust model that Cloud Foundry relies upon for secure user management and access control.
Organizations should immediately implement mitigations including upgrading to patched versions of Cloud Foundry and UAA components, specifically targeting versions that address the session fixation issue. The recommended approach involves applying the vendor-provided security patches and ensuring that all external identity provider configurations properly enforce session management best practices. Additionally, security teams should conduct thorough assessments of their current UAA configurations to identify any systems still running vulnerable versions, implementing network segmentation and monitoring to detect potential exploitation attempts. Organizations should also review their authentication workflows to ensure proper session handling when integrating with external identity providers, following security guidelines that align with the CWE-384 standard for session fixation vulnerabilities and implementing controls consistent with ATT&CK technique T1566 for credential access through authentication bypass methods.