CVE-2017-4943 in vCenter Server Appliance
Summary
by MITRE
VMware vCenter Server Appliance (vCSA) (6.5 before 6.5 U1d) contains a local privilege escalation vulnerability via the 'showlog' plugin. Successful exploitation of this issue could result in a low privileged user gaining root level privileges over the appliance base OS.
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Analysis
by VulDB Data Team • 01/27/2021
The vulnerability identified as CVE-2017-4943 represents a critical local privilege escalation flaw within VMware vCenter Server Appliance version 6.5 prior to 6.5 Update 1d. This security weakness specifically affects the 'showlog' plugin component of the vCSA, which serves as a diagnostic utility for system administrators to view log files. The vulnerability stems from improper privilege handling within the plugin's execution environment, creating a pathway for malicious actors to elevate their system privileges from standard user level to root access. The affected appliance operates on a Linux-based operating system where the showlog plugin fails to properly enforce access controls, allowing unauthorized users to exploit command execution capabilities that should be restricted to privileged system processes.
The technical implementation of this vulnerability involves a flawed permission model within the vCSA's plugin architecture where the showlog utility does not adequately validate user privileges before executing system commands. Attackers can leverage this weakness by crafting specific input parameters that bypass normal access controls, ultimately enabling them to execute arbitrary commands with elevated privileges. This flaw aligns with CWE-276, which categorizes improper privilege management as a fundamental security weakness, and demonstrates how insufficient access control mechanisms can lead to complete system compromise. The vulnerability exists in the context of a trusted application that should only permit authorized administrative access, yet the showlog plugin fails to maintain proper privilege boundaries during its operation.
From an operational impact perspective, successful exploitation of CVE-2017-4943 provides attackers with complete control over the vCenter Server Appliance's underlying operating system, enabling them to manipulate system configurations, access sensitive data, install malicious software, or establish persistent backdoors. This privilege escalation capability directly violates the principle of least privilege and creates an attack surface that can be leveraged for further lateral movement within virtualized environments. The vulnerability is particularly concerning in enterprise settings where vCenter appliances serve as central management points for large-scale virtual infrastructures, as compromise of a single appliance can potentially affect numerous virtual machines and associated resources. Organizations utilizing this vulnerable version face significant risk of data breaches, system disruption, and potential regulatory compliance violations.
The remediation strategy for CVE-2017-4943 requires immediate implementation of VMware's official security patches, specifically targeting VMware vCenter Server Appliance 6.5 Update 1d or later versions. Organizations should also conduct comprehensive security assessments to identify any potential exploitation attempts that may have occurred prior to patch deployment. System administrators should implement additional monitoring controls around the showlog plugin and related system components to detect anomalous behavior patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper privilege separation in application design and highlights the necessity of maintaining current security patches across all system components. Security teams should consider implementing network segmentation and access control measures to limit potential impact if exploitation occurs, while also establishing incident response procedures specifically addressing privilege escalation vulnerabilities in virtualization management platforms. This vulnerability serves as a reminder of the critical nature of maintaining secure configurations in complex enterprise systems and the potential consequences of inadequate privilege management in trusted software components.