CVE-2018-19871 in Qt
Summary
by MITRE
An issue was discovered in Qt before 5.11.3. There is QTgaFile Uncontrolled Resource Consumption.
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Analysis
by VulDB Data Team • 06/22/2023
The vulnerability identified as CVE-2018-19871 represents a critical resource consumption flaw within the Qt framework affecting versions prior to 5.11.3. This issue specifically resides within the QTgaFile component which handles TGA (Targa) image file format processing. The vulnerability manifests when the Qt library attempts to parse maliciously crafted TGA files, leading to excessive memory consumption and potential system resource exhaustion. The flaw stems from inadequate input validation and bounds checking during the parsing of TGA file headers and metadata, allowing attackers to craft specially formatted files that trigger uncontrolled resource allocation within the application processing these images.
This vulnerability falls under the CWE-400 category of Uncontrolled Resource Consumption, which represents a significant threat to system stability and availability. The technical implementation flaw occurs in the QTgaFile class where the library fails to properly validate the dimensions and size parameters specified in TGA file headers. When processing a malformed TGA file, the parsing routine allocates memory based on values specified in the file header without sufficient validation, potentially leading to integer overflows or excessive memory allocation that can cause denial of service conditions. The issue is particularly concerning because TGA files are commonly used in various multimedia applications, graphics software, and game engines that rely on Qt for their user interfaces and image processing capabilities.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it can be exploited in multiple attack vectors within applications that utilize Qt for image handling. An attacker could potentially compromise systems by uploading or delivering malicious TGA files through web applications, email attachments, or file sharing platforms that process these image formats. The resource exhaustion could lead to application crashes, system instability, or complete system hangs, particularly affecting servers or applications that process numerous image files concurrently. This vulnerability is especially dangerous in environments where Qt-based applications handle user-uploaded content, as it could be leveraged for distributed denial of service attacks or to degrade service availability for legitimate users.
Mitigation strategies for CVE-2018-19871 primarily involve immediate upgrading to Qt version 5.11.3 or later, which contains the necessary patches to address the uncontrolled resource consumption issue. Organizations should also implement input validation measures at application level to verify TGA file integrity before processing, including checking file headers against reasonable size constraints and implementing timeout mechanisms for image parsing operations. Network-level defenses can include content filtering solutions that scan for suspicious TGA file characteristics and prevent their delivery to vulnerable applications. Additionally, security teams should conduct comprehensive vulnerability assessments of all Qt-based applications to identify potential exposure points and implement proper resource monitoring to detect abnormal memory consumption patterns that could indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under the T1499.004 subtechnique for Network Denial of Service, highlighting its potential for disrupting service availability through resource exhaustion attacks.