CVE-2020-5396 in GemFire
Summary
by MITRE
VMware GemFire versions prior to 9.10.0, 9.9.2, 9.8.7, and 9.7.6, and VMware Tanzu GemFire for VMs versions prior to 1.11.1 and 1.10.2, when deployed without a SecurityManager, contain a JMX service available which contains an insecure default configuration. This allows a malicious user to create an MLet mbean leading to remote code execution.
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Analysis
by VulDB Data Team • 11/06/2020
The vulnerability identified as CVE-2020-5396 affects VMware GemFire and VMware Tanzu GemFire for VMs products across multiple version lines, specifically those prior to 9.10.0, 9.9.2, 9.8.7, 9.7.6, and their corresponding Tanzu GemFire versions. This security flaw resides in the Java Management Extensions JMX service configuration, which represents a critical weakness in the system's security architecture. The vulnerability manifests when these products are deployed without an active SecurityManager, creating an exploitable attack surface that could allow unauthorized users to execute arbitrary code on affected systems.
The technical exploitation of this vulnerability leverages an insecure default JMX service configuration that permits the creation of MLet MBeans without proper authentication or authorization mechanisms. This insecure default configuration essentially provides a backdoor through which malicious actors can inject and execute arbitrary Java code within the target system's runtime environment. The MLet MBean functionality allows for dynamic loading of Java classes from remote locations, making it particularly dangerous when combined with the lack of security controls in the JMX service. This configuration effectively bypasses normal access controls and provides an execution path that directly leads to remote code execution capabilities.
From an operational perspective, this vulnerability presents a severe risk to organizations deploying VMware GemFire systems without proper security hardening. The impact extends beyond simple privilege escalation to full system compromise, as the remote code execution capability allows attackers to potentially gain complete control over the affected servers. The vulnerability affects systems where default configurations are left unchanged, which represents a common scenario in production environments where security hardening may be overlooked during deployment. Organizations using these older versions face significant risk exposure, particularly in environments where network segmentation is insufficient or where the JMX service is accessible from untrusted networks.
The vulnerability aligns with CWE-284, which addresses improper access control in software systems, and represents a classic case of insecure default configurations that violate fundamental security principles. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and execution of malicious code, with the MLet MBean creation serving as a method for establishing persistent access to target systems. Organizations should implement immediate mitigations including upgrading to patched versions of VMware GemFire, configuring proper SecurityManager implementations, and restricting network access to JMX services. Additionally, security monitoring should be enhanced to detect unusual MBean creation activities and unauthorized JMX service access attempts. The recommended remediation strategy involves comprehensive security hardening of all affected systems, including proper configuration of access controls, network segmentation, and regular security assessments to prevent similar vulnerabilities from emerging in the future.