CVE-2016-5016 in Cloud Foundry
Summary
by MITRE
Pivotal Cloud Foundry 239 and earlier, UAA (aka User Account and Authentication Server) 3.4.1 and earlier, UAA release 12.2 and earlier, PCF (aka Pivotal Cloud Foundry) Elastic Runtime 1.6.x before 1.6.35, and PCF Elastic Runtime 1.7.x before 1.7.13 does not validate if a certificate is expired.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 12/02/2022
The vulnerability described in CVE-2016-5016 represents a critical certificate validation flaw within Pivotal Cloud Foundry's User Account and Authentication Server component. This issue affects multiple versions of the platform including Pivotal Cloud Foundry 239 and earlier, UAA versions 3.4.1 and earlier, UAA release 12.2 and earlier, along with specific versions of PCF Elastic Runtime 1.6.x before 1.6.35 and 1.7.x before 1.7.13. The core problem lies in the absence of proper certificate expiration validation mechanisms within the authentication infrastructure, creating a significant security gap that could be exploited by malicious actors.
The technical flaw manifests as a failure in the certificate validation process where the system does not properly check whether digital certificates have expired before accepting them for authentication purposes. This vulnerability directly maps to CWE-295 which describes "Improper Certificate Validation" and aligns with ATT&CK technique T1552.001 for "Credentials in Files" and T1552.006 for "Credentials in Registry" as attackers could potentially leverage expired certificates for unauthorized access. When certificates are not validated for expiration, the system becomes vulnerable to man-in-the-middle attacks, session hijacking, and unauthorized authentication attempts that bypass normal security controls.
The operational impact of this vulnerability extends beyond simple authentication failures, creating a substantial risk to the overall security posture of cloud environments relying on Pivotal Cloud Foundry. Organizations using affected versions face potential unauthorized access to sensitive systems, data breaches through compromised authentication mechanisms, and increased attack surface for lateral movement within networks. The vulnerability particularly affects environments where certificate-based authentication is critical for securing communications between applications, services, and user accounts. Attackers could exploit this weakness to establish persistent access, escalate privileges, or conduct reconnaissance activities without detection, as the system would accept expired certificates as valid authentication credentials.
Mitigation strategies for CVE-2016-5016 require immediate patching of affected systems to versions that properly validate certificate expiration dates. Organizations should implement comprehensive certificate management policies that include automated monitoring for certificate expiration, regular audits of certificate validity, and enforcement of strict certificate validation procedures. The remediation process should involve upgrading to patched versions of Pivotal Cloud Foundry components, configuring proper certificate validation settings, and implementing additional security controls such as certificate pinning and enhanced monitoring for suspicious authentication patterns. Security teams must also conduct thorough vulnerability assessments to identify any systems that may have been compromised through the use of expired certificates, while ensuring that certificate lifecycle management practices are established to prevent similar issues in the future.