CVE-2020-24741 in Qt
Summary
by MITRE • 08/10/2021
An issue has been fixed in Qt versions 5.14.1 and 5.12.7 where QLibrary 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-2020-24741 represents a critical security flaw in the Qt framework affecting versions 5.14.1 and 5.12.7. This issue stems from how QLibrary handles plugin loading mechanisms within the Qt application architecture. The core problem manifests when applications utilizing Qt attempt to load plugins, as the library searches for these components relative to the current working directory rather than implementing proper secure path resolution. This behavior creates an exploitable condition where malicious actors can manipulate the plugin loading process by placing specially crafted files in the working directory, thereby enabling arbitrary code execution. The vulnerability directly relates to CWE-427 Uncontrolled Search Path Element, which occurs when an application searches for resources in directories that can be manipulated by attackers. This weakness is particularly dangerous because it allows for privilege escalation and remote code execution in applications that rely on Qt's plugin architecture.
The technical implementation of this vulnerability involves Qt's QLibrary class which is responsible for dynamic loading of shared libraries and plugins within applications. When QLibrary attempts to load plugins, it does not properly validate or sanitize the search paths, instead relying on the system's current working directory. Attackers can exploit this by placing malicious plugin files with identical names to legitimate plugins in the working directory from which the Qt application is executed. The application will then load the malicious plugin instead of the intended legitimate one, leading to arbitrary code execution. This flaw demonstrates a classic path traversal and privilege escalation vulnerability where the working directory is not properly secured or validated. The attack vector becomes particularly effective in environments where applications are executed with elevated privileges or when users can influence the working directory through various means such as file system manipulation or directory traversal attacks.
The operational impact of CVE-2020-24741 extends across numerous applications that utilize Qt frameworks, particularly those that dynamically load plugins or libraries. Applications affected include but are not limited to desktop applications, multimedia players, development tools, and enterprise software that rely on Qt's plugin architecture for extensibility. The vulnerability can be exploited remotely through various attack vectors including web-based attacks, file sharing scenarios, or when users are tricked into executing malicious code in specific working directories. The exploitability of this vulnerability is significantly enhanced in environments where users have the ability to control or influence the working directory of Qt applications, or where applications are run with elevated privileges. Organizations using affected Qt versions face potential data breaches, system compromise, and unauthorized access to sensitive information, making this vulnerability particularly concerning for enterprise security.
Mitigation strategies for CVE-2020-24741 primarily focus on upgrading to patched versions of Qt framework, specifically versions 5.14.1 and 5.12.7 or later releases that contain the necessary security fixes. Organizations should implement comprehensive patch management processes to ensure all affected applications are updated promptly. Additionally, defensive programming practices should be enforced within Qt applications to explicitly define and validate plugin search paths, avoiding reliance on relative paths from the working directory. System administrators should consider implementing security measures such as application whitelisting, restricted file system permissions, and monitoring for suspicious plugin loading activities. The vulnerability aligns with ATT&CK technique T1059 Command and Scripting Interpreter, as it enables attackers to execute arbitrary code through legitimate system processes. Organizations should also implement network segmentation and access controls to limit potential attack surfaces and reduce the impact of successful exploitation attempts. Proper code review practices should be implemented to ensure Qt applications do not inadvertently rely on insecure plugin loading mechanisms.