CVE-2023-40889 in ZBar
Summary
by MITRE • 08/29/2023
A heap-based buffer overflow exists in the qr_reader_match_centers function of ZBar 0.23.90. Specially crafted QR codes may lead to information disclosure and/or arbitrary code execution. To trigger this vulnerability, an attacker can digitally input the malicious QR code, or prepare it to be physically scanned by the vulnerable scanner.
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Analysis
by VulDB Data Team • 11/23/2024
The heap-based buffer overflow vulnerability in ZBar 0.23.90 represents a critical security flaw within the qr_reader_match_centers function that can be exploited through specially crafted QR codes. This vulnerability falls under the CWE-121 heap-based buffer overflow category, where insufficient bounds checking allows malicious data to overwrite adjacent heap memory locations. The flaw specifically affects the QR code parsing functionality of the ZBar library, which is widely used in various applications for barcode and QR code recognition. Attackers can leverage this vulnerability by preparing malicious QR codes that, when processed by the vulnerable software, trigger the buffer overflow condition. The vulnerability exists because the function does not properly validate the size of input data before copying it into heap-allocated buffers, creating opportunities for memory corruption that can be exploited for arbitrary code execution.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable full system compromise through arbitrary code execution. When a malicious QR code is processed, the buffer overflow can overwrite critical memory structures including return addresses, function pointers, or other control data within the heap memory space. This memory corruption can lead to unpredictable behavior including application crashes, information disclosure through memory leaks, or more seriously, remote code execution when the corrupted memory locations are subsequently used in program execution. The vulnerability is particularly concerning because QR code scanning is commonly performed in mobile applications, point-of-sale systems, and security devices where users may not be aware they are interacting with malicious content. The attack vector is accessible through both digital input and physical scanning, making it applicable in various real-world scenarios including mobile applications, web-based QR code readers, and hardware-based scanners that utilize the vulnerable ZBar library.
Mitigation strategies for this vulnerability require immediate action including updating to patched versions of the ZBar library where available, implementing input validation controls, and deploying runtime protections such as stack canaries, address space layout randomization, and heap integrity checks. Organizations should conduct thorough vulnerability assessments to identify all systems using vulnerable versions of ZBar and ensure proper patch management procedures are in place. The ATT&CK framework categorizes this vulnerability under T1557.001 for "Adversary-in-the-Middle" and T1059.001 for "Command and Scripting Interpreter" as attackers may use this vulnerability to execute malicious code on target systems. Additionally, implementing network-level controls to restrict QR code scanning in sensitive environments, using sandboxed execution environments for QR code processing, and deploying intrusion detection systems that can identify suspicious QR code patterns can provide additional layers of defense. Security teams should also consider implementing application whitelisting policies that restrict execution of code from untrusted QR code sources and establish monitoring procedures to detect anomalous QR code processing activities that might indicate exploitation attempts.