CVE-2017-16839 in vagrant-vmware-fusion
Summary
by MITRE
Hashicorp vagrant-vmware-fusion 5.0.4 allows local users to steal root privileges if VMware Fusion is not installed.
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Analysis
by VulDB Data Team • 01/18/2020
The vulnerability identified as CVE-2017-16839 affects Hashicorp vagrant-vmware-fusion version 5.0.4 and represents a critical privilege escalation flaw that exploits the absence of proper validation mechanisms within the virtualization management software. This issue arises when VMware Fusion is not installed on the target system, creating a dangerous condition where local users can potentially escalate their privileges to root access through malformed system calls or improper privilege handling within the vagrant-vmware-fusion plugin. The vulnerability stems from inadequate input validation and privilege separation mechanisms that fail to properly authenticate or authorize system-level operations when the expected virtualization environment is missing.
The technical implementation of this flaw involves the vagrant-vmware-fusion plugin attempting to execute privileged operations without verifying the presence or proper configuration of the VMware Fusion virtualization environment. When VMware Fusion is absent from the system, the plugin falls back to insecure code paths that do not properly validate user privileges or implement appropriate access controls. This creates a privilege escalation vector where unprivileged users can manipulate system calls to gain elevated privileges, effectively bypassing the standard operating system security controls. The vulnerability operates under the principle of insecure privilege handling and improper access control enforcement as classified by CWE-276, which specifically addresses improper privilege management and inadequate access control mechanisms.
The operational impact of CVE-2017-16839 extends beyond simple privilege escalation to potentially enable full system compromise and unauthorized access to sensitive data. An attacker exploiting this vulnerability could gain root access to the system, allowing them to modify critical system files, install malicious software, access confidential information, and establish persistent backdoors. This vulnerability particularly affects environments where vagrant-vmware-fusion is installed but VMware Fusion is not properly configured or installed, creating a mismatch between the expected and actual system state. The flaw aligns with ATT&CK technique T1068 which covers privilege escalation through insecure software configuration, and T1548 which addresses abuse of privilege escalation techniques through system-level software.
Security mitigations for this vulnerability require immediate patching of the vagrant-vmware-fusion plugin to version 5.0.5 or later, which implements proper validation checks for the VMware Fusion installation status and appropriate privilege handling mechanisms. System administrators should also implement proper access controls and privilege separation, ensuring that only authorized users can install or modify virtualization plugins. The recommended approach includes disabling unnecessary virtualization plugins when VMware Fusion is not present, implementing proper file permissions for vagrant-vmware-fusion components, and conducting regular security audits to identify similar privilege escalation vulnerabilities in other system components. Additionally, organizations should consider implementing principle of least privilege access controls and monitoring for suspicious privilege escalation attempts that could indicate exploitation of similar vulnerabilities.