CVE-2010-5247 in QtWeb
Summary
by MITRE
Untrusted search path vulnerability in QtWeb Browser 3.3 build 043 allows local users to gain privileges via a Trojan horse wintab32.dll file in the current working directory, as demonstrated by a directory that contains a .html, .htm, or .mhtml file. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 02/20/2019
The vulnerability identified as CVE-2010-5247 represents a critical untrusted search path issue within QtWeb Browser version 3.3 build 043 that enables local privilege escalation through malicious DLL injection techniques. This flaw exists in the browser's dynamic link library loading mechanism where the application fails to properly validate the source and integrity of dynamically loaded libraries. The vulnerability specifically manifests when the browser processes web content files with extensions .html, .htm, or .mhtml, creating a scenario where an attacker can place a malicious wintab32.dll file in the same directory as these web files. This particular DLL name choice is significant as wintab32.dll is a legitimate Windows system file that the browser may attempt to load during normal operation, making the attack vector more subtle and harder to detect. The underlying technical flaw aligns with CWE-426, which describes the insecure loading of dynamic libraries where applications search for libraries in untrusted paths before checking trusted system directories. This vulnerability operates at the operating system level where the browser's execution context allows for arbitrary code execution through the loaded malicious DLL, effectively bypassing normal security boundaries that would typically prevent such privilege escalation. The attack scenario involves a local user placing a crafted wintab32.dll file in the directory containing web content files, which then gets loaded when the browser processes these files, resulting in arbitrary code execution with the privileges of the user running the browser. The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with a reliable method to execute malicious code within the browser's security context, potentially leading to full system compromise. This vulnerability also demonstrates characteristics consistent with ATT&CK technique T1059.001 for command and script interpreter and T1068 for exploit for privilege escalation, as it leverages the browser's legitimate DLL loading behavior to achieve unauthorized code execution. The attack vector is particularly concerning because it requires minimal user interaction beyond opening a web file, making it suitable for social engineering campaigns where users might inadvertently trigger the malicious code execution. The vulnerability's persistence across different file types (.html, .htm, .mhtml) indicates a systemic issue in how the browser handles dynamic library loading regardless of content type, suggesting the flaw exists in the core library loading mechanism rather than specific file processing code. Security researchers have noted that this vulnerability highlights the importance of proper DLL search path management and the dangers of relying on default system paths without explicit validation of library sources. The exploitation of this vulnerability also underscores the broader security principle that applications should never trust dynamic library loading from unverified sources and should implement explicit path validation to prevent attackers from placing malicious libraries in directories that are searched by default. Organizations should consider this vulnerability as part of a larger attack surface that includes other DLL hijacking techniques and should implement comprehensive application whitelisting policies to prevent unauthorized code execution. The remediation approach requires immediate patching of the QtWeb Browser to ensure proper validation of library loading paths and implementation of secure coding practices that prevent untrusted search path vulnerabilities. System administrators should also consider implementing monitoring for suspicious DLL loading activities and establishing baseline behaviors for legitimate applications to detect anomalous loading patterns that might indicate exploitation attempts.