CVE-2020-0779 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists in the Windows Installer when MSI packages process symbolic links, aka 'Windows Installer Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2020-0798, CVE-2020-0814, CVE-2020-0842, CVE-2020-0843.
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Analysis
by VulDB Data Team • 04/10/2024
The vulnerability identified as CVE-2020-0779 represents a critical elevation of privilege flaw within the Windows Installer component that specifically manifests when processing symbolic links in MSI packages. This weakness allows attackers to escalate their privileges from standard user level to system level execution, creating a significant security risk for Windows environments. The vulnerability stems from improper handling of symbolic link resolution during the installation process, where the installer fails to properly validate or sanitize symbolic link references that could point to privileged system locations.
The technical flaw occurs within the Windows Installer service which processes MSI package files containing symbolic links that may reference system directories or files with elevated permissions. When the installer encounters such symbolic links, it follows them without adequate verification of the target location, potentially allowing an attacker to redirect installation operations to write files in protected system locations. This behavior violates fundamental security principles of privilege separation and access control enforcement. The vulnerability is categorized under CWE-264, which addresses permissions, privileges, and access controls, specifically focusing on inadequate privilege management during file operations. The flaw enables attackers to manipulate the installation process to execute arbitrary code with system-level privileges, bypassing normal security boundaries that should prevent standard users from modifying protected system components.
Operationally, this vulnerability presents a severe threat to enterprise environments where users may have the ability to execute MSI packages or where automated deployment systems process untrusted installation packages. Attackers can exploit this weakness by crafting malicious MSI packages that contain carefully constructed symbolic links pointing to system binaries or configuration files. The impact extends beyond simple privilege escalation to include potential system compromise, data theft, and persistence mechanisms. This vulnerability aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation' and specifically addresses how adversaries can leverage software vulnerabilities to gain elevated privileges. Organizations running Windows systems are particularly vulnerable when they allow users to execute installation packages or when automated processes handle untrusted MSI files without proper sandboxing or validation mechanisms.
Mitigation strategies for CVE-2020-0779 should focus on immediate patch management through Microsoft's security updates, which address the symbolic link processing behavior in Windows Installer. System administrators should implement strict access controls to prevent unauthorized users from executing installation packages and establish proper code signing policies for MSI files. Organizations should deploy application whitelisting solutions to restrict which installation packages can be executed and implement monitoring solutions to detect suspicious installation activities. Additionally, network segmentation and privilege minimization practices should be enforced to limit the potential impact of successful exploitation. The vulnerability demonstrates the importance of secure coding practices in system components and highlights the need for comprehensive security testing of installation and deployment mechanisms. Regular security assessments of Windows Installer configurations and proper system hardening measures should be implemented to prevent exploitation of similar weaknesses in the broader Windows ecosystem.