CVE-2012-6093 in Digia
Summary
by MITRE
The QSslSocket::sslErrors function in Qt before 4.6.5, 4.7.x before 4.7.6, 4.8.x before 4.8.5, when using certain versions of openSSL, uses an "incompatible structure layout" that can read memory from the wrong location, which causes Qt to report an incorrect error when certificate validation fails and might cause users to make unsafe security decisions to accept a certificate.
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Analysis
by VulDB Data Team • 12/29/2021
The vulnerability identified as CVE-2012-6093 represents a critical flaw in the Qt framework's SSL socket implementation that affects multiple version ranges including Qt 4.6.x before 4.6.5, 4.7.x before 4.7.6, and 4.8.x before 4.8.5. This issue specifically impacts the QSslSocket::sslErrors function when interfacing with certain OpenSSL versions, creating a fundamental architectural incompatibility that undermines the security validation process. The problem stems from an incompatible structure layout between Qt's SSL error handling mechanism and the underlying OpenSSL library, which creates a dangerous misalignment in memory access patterns. When certificate validation fails, this flaw causes Qt applications to report incorrect SSL errors to developers and end users, potentially leading to security decisions based on misleading information.
The technical implementation of this vulnerability resides in how Qt handles SSL certificate validation errors through its QSslSocket::sslErrors function. When OpenSSL processes certificate validation and encounters failures, the incompatible structure layout causes Qt to access memory locations that contain incorrect error data rather than the actual validation results. This memory access issue originates from a mismatch between the expected data structure layout in Qt's error handling code and the actual structure layout provided by specific OpenSSL versions. The flaw essentially creates a situation where error codes and validation status information are read from incorrect memory addresses, resulting in corrupted error reporting that can mislead applications into accepting invalid certificates or making incorrect security decisions.
The operational impact of CVE-2012-6093 extends beyond simple error reporting failures to potentially compromise the security posture of applications relying on Qt's SSL capabilities. Applications using affected Qt versions may present users with false security warnings or misleading error messages during certificate validation processes, which could lead users to accept certificates they would otherwise reject. This vulnerability particularly affects applications that implement custom SSL error handling or rely on specific error codes for security decision-making processes. The flaw creates a scenario where security-conscious users might be tricked into accepting compromised certificates, effectively bypassing the intended security checks that should prevent connections to untrusted servers. This type of vulnerability directly impacts the CIA triad, specifically compromising the integrity and confidentiality aspects of secure communications.
Organizations and developers must implement immediate mitigations to address this vulnerability, primarily by upgrading to patched versions of the Qt framework that resolve the structure layout incompatibility. The recommended approach involves updating to Qt 4.6.5, 4.7.6, or 4.8.5, which contain the necessary fixes for the memory access issues in the QSslSocket::sslErrors function. Additionally, administrators should conduct thorough vulnerability assessments to identify all applications using affected Qt versions and ensure proper patch management protocols are followed. Security teams should monitor for applications that might implement custom SSL error handling logic that could be affected by this vulnerability, as these applications may require additional code modifications to properly handle certificate validation errors. The vulnerability aligns with CWE-125: Out-of-Bounds Read, which describes the scenario where programs access memory locations beyond their intended bounds, and potentially maps to ATT&CK technique T1566.001: Phishing, as compromised SSL validation could enable man-in-the-middle attacks through certificate spoofing. This vulnerability demonstrates the critical importance of maintaining compatibility between cryptographic libraries and application frameworks, as even subtle structural mismatches can create significant security risks that affect the entire SSL/TLS validation chain.