CVE-2016-6659 in Cloud Foundry
Summary
by MITRE
Cloud Foundry before 248; UAA 2.x before 2.7.4.12, 3.x before 3.6.5, and 3.7.x through 3.9.x before 3.9.3; and UAA bosh release (aka uaa-release) before 13.9 for UAA 3.6.5 and before 24 for UAA 3.9.3 allow attackers to gain privileges by accessing UAA logs and subsequently running a specially crafted application that interacts with a configured SAML provider.
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Analysis
by VulDB Data Team • 07/14/2019
The vulnerability described in CVE-2016-6659 represents a critical privilege escalation flaw affecting Cloud Foundry platforms and its User Account and Authentication (UAA) service. This issue stems from insufficient access controls and logging mechanisms within the UAA component, which serves as the central authentication service for Cloud Foundry deployments. The vulnerability affects multiple versions of Cloud Foundry's UAA service including 2.x versions before 2.7.4.12, 3.x versions before 3.6.5, and specific 3.7.x versions before 3.9.3, along with corresponding BOSH releases. The flaw allows attackers with access to UAA logs to escalate their privileges by executing carefully crafted applications that interact with configured SAML identity providers, creating a dangerous chain of exploitation.
The technical root cause of this vulnerability lies in the improper handling of authentication tokens and session management within the UAA service. When attackers gain access to UAA log files, they can extract sensitive information including authentication tokens, session identifiers, and other credential material that should remain protected. The vulnerability specifically exploits the interaction between the UAA service and SAML providers, where the system fails to properly validate or sanitize the authentication flow when applications connect to these identity providers. This creates an opportunity for privilege escalation attacks where malicious actors can leverage legitimate authentication flows to assume elevated privileges within the Cloud Foundry environment. The flaw aligns with CWE-287 which addresses improper authentication issues, and represents a classic case of insecure credential handling in enterprise authentication systems.
The operational impact of CVE-2016-6659 is severe and multifaceted across Cloud Foundry deployments. Organizations running affected versions of Cloud Foundry face potential complete compromise of their platform security, as attackers can move laterally through the system and assume administrative privileges. The vulnerability undermines the fundamental security model of Cloud Foundry by allowing unauthorized access to critical system resources, potentially enabling data exfiltration, service disruption, and complete platform takeover. Attackers can exploit this vulnerability to gain access to user accounts, application data, and underlying infrastructure resources, making it particularly dangerous in multi-tenant environments where isolation between users is critical. The impact extends beyond immediate privilege escalation to include potential long-term persistence mechanisms within the platform.
Mitigation strategies for CVE-2016-6659 require immediate version upgrades to patched releases of Cloud Foundry and UAA components. Organizations should upgrade to UAA versions 2.7.4.12, 3.6.5, and 3.9.3 or later, along with corresponding BOSH releases. System administrators must implement strict access controls for UAA log files, ensuring that only authorized personnel can access these sensitive artifacts. The remediation process should include disabling or properly configuring SAML providers to prevent unauthorized applications from accessing authentication flows. Additionally, organizations should conduct thorough security audits of their Cloud Foundry deployments to identify and remove any applications that might be vulnerable to this exploitation technique. Security monitoring should be enhanced to detect unusual access patterns to authentication logs and suspicious SAML interactions. This vulnerability demonstrates the importance of implementing defense-in-depth strategies and adheres to ATT&CK techniques related to privilege escalation and credential access, specifically targeting the T1078 and T1566 tactics used by adversaries to gain unauthorized access to systems.