CVE-2016-3711 in OpenShift Enterprise
Summary
by MITRE
HAproxy in Red Hat OpenShift Enterprise 3.2 and OpenShift Origin allows local users to obtain the internal IP address of a pod by reading the "OPENSHIFT_[namespace]_SERVERID" cookie.
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Analysis
by VulDB Data Team • 08/23/2022
The vulnerability described in CVE-2016-3711 represents a significant information disclosure issue within the HAproxy implementation used in Red Hat OpenShift Enterprise 3.2 and OpenShift Origin environments. This flaw allows local attackers to extract sensitive internal network information through manipulation of specific cookie values, creating potential attack vectors for further exploitation. The vulnerability specifically targets the cookie management mechanism within the OpenShift container platform's load balancing infrastructure.
The technical implementation of this vulnerability stems from improper handling of the "OPENSHIFT_[namespace]_SERVERID" cookie within the HAproxy configuration. When local users access certain endpoints within the OpenShift environment, the system inadvertently exposes internal pod IP addresses through the cookie value structure. This occurs because the cookie contains serialized internal network identifiers that are not properly sanitized or obfuscated before being made available to local processes. The flaw exists at the application layer where cookie generation and processing logic fails to adequately protect internal network topology information.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with critical network mapping data that could facilitate more sophisticated attacks. An attacker who successfully exploits this vulnerability gains visibility into the internal pod network structure, which could be used to identify target systems, understand network segmentation, and plan subsequent attacks. This information disclosure could enable attackers to bypass network security controls or launch targeted attacks against specific internal services. The vulnerability affects the core container orchestration functionality and undermines the security isolation properties that container platforms are designed to maintain.
Organizations implementing OpenShift environments should immediately apply the vendor-provided patches and updates to address this vulnerability. The recommended mitigation strategy involves configuring proper cookie sanitization mechanisms within HAproxy to prevent internal IP address exposure through cookie values. Security teams should also implement network monitoring to detect unusual cookie access patterns and consider implementing additional access controls to limit local user privileges within container environments. This vulnerability aligns with CWE-200, which covers improper exposure of sensitive information, and could potentially support techniques described in the ATT&CK framework under reconnaissance and credential access phases. The issue demonstrates the importance of proper input validation and output sanitization in containerized environments where internal network information is exposed through application interfaces.