CVE-2019-6173 in Installation Package
Summary
by MITRE
A DLL search path vulnerability could allow privilege escalation in some Lenovo installation packages, prior to version 1.2.9.3, during installation if an attacker already has administrative privileges.
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Analysis
by VulDB Data Team • 10/23/2020
The vulnerability identified as CVE-2019-6173 represents a critical DLL search path issue that could enable privilege escalation within Lenovo installation packages. This weakness specifically affects versions prior to 1.2.9.3 and operates under the assumption that an attacker already possesses administrative privileges. The vulnerability stems from improper handling of dynamic link library loading sequences during the installation process, creating opportunities for malicious code execution with elevated privileges. The issue manifests when the installation package fails to properly specify the location of required DLL files, allowing the system to search through multiple directories in an insecure manner. This insecure search order can be exploited by placing malicious DLL files in directories that are searched before the legitimate system directories, effectively enabling code injection during the installation phase.
The technical flaw underlying CVE-2019-6173 aligns with CWE-427, which describes uncontrolled search path behavior that allows attackers to load malicious code instead of intended libraries. This vulnerability operates at the operating system level where the dynamic link library loader performs searches through a predefined path sequence. When an application or installation process loads a DLL without specifying its full path, the system follows a standard search order that includes the current working directory, system directories, and user directories. The vulnerability occurs when this search order is not properly secured, allowing an attacker with administrative access to place malicious DLLs in directories that are searched before legitimate system libraries. The exploitation mechanism leverages the fact that installation packages often run with elevated privileges, making the potential impact significantly more severe than typical user-level vulnerabilities.
The operational impact of CVE-2019-6173 extends beyond simple privilege escalation to potentially enable full system compromise when combined with other attack vectors. While the vulnerability requires pre-existing administrative privileges, it provides attackers with a persistent mechanism to maintain elevated access and execute malicious code with the privileges of the installation process. This capability is particularly concerning in enterprise environments where Lenovo installation packages are commonly deployed across multiple systems. The vulnerability can be exploited to maintain persistence, escalate privileges further, or establish backdoors that survive system reboots. Attackers can leverage this weakness to execute arbitrary code with administrative privileges, potentially leading to complete system compromise and data exfiltration. The vulnerability's impact is amplified in environments where automated deployment tools or group policies frequently execute Lenovo installation packages, as these scenarios provide multiple opportunities for exploitation.
Mitigation strategies for CVE-2019-6173 should focus on both immediate remediation and long-term security hardening. The primary solution involves updating to Lenovo installation packages version 1.2.9.3 or later, which addresses the insecure DLL search path behavior through proper path specification and secure loading mechanisms. Organizations should implement comprehensive patch management processes to ensure all affected systems receive updates promptly. Additionally, security teams should conduct thorough vulnerability assessments to identify any remaining systems that may still be running vulnerable versions of Lenovo installation packages. System administrators should also consider implementing application whitelisting policies that restrict which DLLs can be loaded by installation processes, as well as monitoring for unusual file access patterns during installation procedures. Network segmentation and privileged access controls should be reinforced to limit the potential impact of successful exploitation attempts, while regular security audits should verify that installation processes are not vulnerable to similar search path issues. The remediation process should include verification that all installation packages properly specify DLL paths and that the system search order is not susceptible to manipulation by unauthorized users.