CVE-2017-4939 in Workstation
Summary
by MITRE
VMware Workstation (12.x before 12.5.8) installer contains a DLL hijacking issue that exists due to some DLL files loaded by the application improperly. This issue may allow an attacker to load a DLL file of the attacker's choosing that could execute arbitrary code.
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Analysis
by VulDB Data Team • 01/24/2021
The vulnerability identified as CVE-2017-4939 represents a critical DLL hijacking flaw within VMware Workstation version 12.x prior to 12.5.8. This security weakness stems from the installer's improper handling of dynamic link library files during the installation process. The flaw occurs when the application loads certain DLL components without specifying their full paths, creating an opportunity for malicious actors to intercept and replace legitimate system libraries with crafted malicious versions. Such an issue fundamentally undermines the integrity of the installation process and provides a potential attack vector for privilege escalation.
The technical implementation of this vulnerability aligns with CWE-426, which describes the insecure loading of dynamic libraries, and specifically manifests as a path traversal issue where the application searches for DLL files in predictable locations without proper validation. The attacker can exploit this by placing a malicious DLL with the same name as a required library in a location that gets searched before the legitimate library, typically in the current working directory or other directories with lower priority in the Windows DLL search order. This behavior creates a window of opportunity for code execution during the installation process when the application loads these untrusted libraries.
From an operational perspective, this vulnerability presents significant risks to organizations using affected VMware Workstation versions, as it enables attackers to execute arbitrary code with the privileges of the user performing the installation. The attack typically requires local access to the system and the ability to influence the installation environment, but once successful, it can lead to complete system compromise. The impact extends beyond simple code execution, potentially allowing attackers to escalate privileges, install backdoors, or establish persistent access to the compromised system. This vulnerability is particularly concerning in enterprise environments where administrative privileges are frequently used for software installation activities.
Mitigation strategies for CVE-2017-4939 should prioritize immediate patching of affected VMware Workstation installations to version 12.5.8 or later, which addresses the DLL loading issues through proper path resolution and library validation. Organizations should also implement strict access controls to prevent unauthorized users from modifying installation directories or creating malicious DLL files in locations where legitimate software may load libraries. Additional protective measures include deploying application whitelisting solutions to restrict execution of unauthorized DLL files, monitoring for suspicious file creation patterns in installation directories, and conducting regular security assessments of software installation processes. The vulnerability's classification under ATT&CK technique T1059.001 for command and scripting interpreter and T1068 for exploit for privilege escalation highlights the need for comprehensive endpoint protection and privilege management controls. Security teams should also consider implementing security awareness training to prevent social engineering attacks that might exploit this vulnerability through deceptive installation scenarios.