CVE-2020-24742 in Qt
Summary
by MITRE • 08/10/2021
An issue has been fixed in Qt versions 5.14.0 where QPluginLoader attempts to load plugins relative to the working directory, allowing attackers to execute arbitrary code via crafted files.
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Analysis
by VulDB Data Team • 08/14/2021
The vulnerability identified as CVE-2020-24742 represents a critical security flaw in Qt framework versions 5.14.0 and earlier, where the QPluginLoader component exhibits insecure loading behavior that can be exploited for arbitrary code execution. This issue stems from the plugin loader's improper handling of plugin paths, specifically its tendency to search for plugins relative to the current working directory rather than enforcing secure path resolution mechanisms. The flaw allows attackers to manipulate the plugin loading process by placing maliciously crafted plugin files in strategic locations within the application's working directory, thereby bypassing normal security boundaries that would typically prevent unauthorized code execution.
From a technical perspective, the vulnerability manifests when applications utilizing Qt's QPluginLoader component fail to properly validate or sanitize the plugin loading paths. The QPluginLoader class is designed to dynamically load plugins at runtime, but in affected versions it does not adequately restrict the search paths to only trusted locations. This behavior creates a path traversal and privilege escalation vector where an attacker can place a malicious plugin file in the working directory and influence the application to load and execute this malicious code. The issue is particularly concerning because it operates at the core of Qt's plugin architecture, which is widely used across numerous applications and systems, making the attack surface extensive and potentially devastating.
The operational impact of CVE-2020-24742 extends far beyond simple code execution, as it can be leveraged to achieve complete system compromise when applications running with elevated privileges are affected. The vulnerability aligns with CWE-276, which addresses improper privileges, and can be mapped to ATT&CK technique T1106 for execution through valid user privileges, as well as T1059 for command and script injection. Applications that rely on Qt's plugin architecture for extending functionality become prime targets for exploitation, particularly those running in environments where user input or file system access might be manipulated by attackers. The vulnerability's exploitation typically requires a scenario where an attacker can influence the working directory or place malicious files in locations where the application will attempt to load plugins.
Organizations and developers should implement immediate mitigations by upgrading to Qt version 5.14.1 or later, where the issue has been addressed through proper path validation and secure plugin loading mechanisms. Additional defensive measures include implementing strict file system access controls, monitoring plugin loading activities, and ensuring that applications running Qt components are not executed with elevated privileges when possible. The vulnerability demonstrates the importance of secure coding practices in framework components and highlights the need for comprehensive input validation and path resolution mechanisms. Security teams should also conduct thorough audits of applications using Qt frameworks to identify potential exposure and implement appropriate monitoring to detect anomalous plugin loading behaviors that might indicate exploitation attempts.