CVE-2004-0693 in Trolltech
Summary
by MITRE
The GIF parser in the QT library (qt3) before 3.3.3 allows remote attackers to cause a denial of service (application crash) via a malformed image file that triggers a null dereference, a different vulnerability than CVE-2004-0692.
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Analysis
by VulDB Data Team • 07/12/2025
The vulnerability identified as CVE-2004-0693 represents a critical denial of service flaw within the Qt3 library's GIF image parsing component. This issue affects versions of the Qt toolkit prior to 3.3.3 and demonstrates how image processing libraries can become attack vectors for system disruption. The vulnerability specifically resides in the GIF parser implementation where improper handling of malformed image data leads to application instability. Security researchers have categorized this as a null pointer dereference condition that occurs during image parsing operations, making it particularly dangerous in environments where applications process untrusted image content from external sources.
The technical exploitation of this vulnerability occurs when a maliciously crafted GIF file is processed by an application utilizing the vulnerable Qt3 library. The malformed image data triggers a null pointer dereference within the GIF parsing code path, causing the application to crash abruptly. This behavior aligns with CWE-476 which describes null pointer dereference conditions that can lead to application termination. The vulnerability differs from CVE-2004-0692 in its specific code path and triggering mechanism, though both affect the same library component. The flaw manifests during the parsing phase when the application attempts to access memory locations that have not been properly initialized, resulting in segmentation faults or similar system crashes.
From an operational perspective, this vulnerability poses significant risk to applications that handle user-uploaded images or process images from untrusted sources. Web applications, image processing services, and multimedia applications using Qt3 are particularly vulnerable as they may encounter malformed GIF files from various origins. The impact extends beyond simple service disruption to potentially enable more sophisticated attacks if attackers can leverage the application crash to execute additional malicious code or cause cascading failures in dependent systems. This vulnerability particularly affects systems where the Qt3 library is used for GUI applications, embedded systems, and any environment where image processing is a core functionality.
Mitigation strategies for CVE-2004-0693 primarily involve upgrading to Qt3 version 3.3.3 or later, which includes fixes for the null pointer dereference issue. Organizations should conduct comprehensive vulnerability assessments to identify all applications utilizing vulnerable Qt3 versions and prioritize patching based on risk exposure. Additionally, implementing input validation and sanitization measures can provide defense-in-depth protection by rejecting malformed image files before they reach the vulnerable parsing code. Security monitoring should include detection of unusual application crash patterns that may indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under defensive evasion techniques where adversaries may attempt to disrupt system services through resource exhaustion or application crashes, making proper patch management and input validation essential defensive measures.