CVE-2013-0254 in Diga plc
Summary
by MITRE
The QSharedMemory class in Qt 5.0.0, 4.8.x before 4.8.5, 4.7.x before 4.7.6, and other versions including 4.4.0 uses weak permissions (world-readable and world-writable) for shared memory segments, which allows local users to read sensitive information or modify critical program data, as demonstrated by reading a pixmap being sent to an X server.
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Analysis
by VulDB Data Team • 05/04/2021
The vulnerability identified as CVE-2013-0254 represents a critical security flaw within the Qt framework's QSharedMemory implementation across multiple versions including Qt 5.0.0 and various 4.8.x and 4.7.x releases. This issue stems from the improper configuration of shared memory segment permissions, where the system creates memory segments with overly permissive access controls that grant world-readable and world-writable privileges. The flaw manifests in the Qt library's approach to managing inter-process communication through shared memory mechanisms, which are fundamental to Qt applications that require efficient data sharing between processes.
The technical implementation of this vulnerability involves the QSharedMemory class failing to properly set restrictive permissions when creating shared memory segments. When Qt applications utilize shared memory for data exchange, particularly in scenarios involving graphical operations such as pixmap transmission to X servers, the underlying memory segments are created with default permissions that allow any local user to access them. This design flaw creates a privilege escalation vector where malicious local users can exploit the weak permissions to gain unauthorized access to sensitive information stored within these memory segments. The vulnerability specifically impacts applications that rely on Qt's shared memory functionality for inter-process communication, making it particularly dangerous in environments where multiple users share the same system resources.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables attackers to modify critical program data that could lead to application instability, data corruption, or even arbitrary code execution within the context of the affected Qt applications. When shared memory segments contain sensitive data such as pixmap information being transmitted to X servers, local users can potentially intercept or manipulate this data to alter the visual output of applications or inject malicious content. This type of vulnerability aligns with CWE-276, which addresses improper permissions for a resource, and represents a classic example of inadequate access control in system components. The attack surface is particularly broad since Qt is widely used across various desktop and embedded applications, making numerous software products potentially vulnerable to this weakness.
Mitigation strategies for CVE-2013-0254 require immediate updates to affected Qt versions, with the most effective solution being the adoption of Qt 4.8.5, 4.7.6, or later releases where the shared memory permission handling has been properly addressed. System administrators should also implement additional security measures such as monitoring for unauthorized access attempts to shared memory segments and reviewing application permissions. The vulnerability demonstrates the importance of proper resource management in cross-platform frameworks and highlights the need for security-conscious development practices. Organizations should conduct thorough vulnerability assessments to identify all applications built with affected Qt versions and ensure timely patching. From an ATT&CK perspective, this vulnerability maps to privilege escalation techniques and resource hijacking, as it allows local users to gain unauthorized access to shared resources that should remain protected. The issue also underscores the necessity of implementing least privilege principles in shared memory management and proper permission enforcement mechanisms within system libraries.