CVE-2017-15779 in XnView Classic
Summary
by MITRE
XnView Classic for Windows Version 2.43 allows attackers to execute arbitrary code or cause a denial of service via a crafted .dwg file, related to "Data from Faulting Address controls subsequent Write Address starting at CADImage+0x00000000000034b0."
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Analysis
by VulDB Data Team • 01/19/2021
The vulnerability CVE-2017-15779 represents a critical buffer overflow flaw in XnView Classic for Windows version 2.43 that enables remote code execution or denial of service through maliciously crafted .dwg files. This vulnerability specifically manifests within the CADImage parsing component where data from a faulting address directly controls subsequent write operations at a specific memory offset. The flaw occurs during the processing of AutoCAD Drawing files, which are commonly used in engineering and architectural applications, making this vulnerability particularly dangerous in professional environments where such file formats are frequently encountered.
The technical implementation of this vulnerability stems from improper input validation within the CAD image parsing logic. When XnView Classic processes a malicious .dwg file, the application fails to properly bounds-check data retrieved from a faulting memory address, allowing an attacker to manipulate the subsequent write operations that begin at offset 0x00000000000034b0 within the CADImage structure. This memory address corresponds to a location where the application attempts to write data without adequate validation, creating a classic buffer overflow condition that can be exploited to overwrite adjacent memory locations. The vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and also relates to CWE-787, representing out-of-bounds write vulnerabilities that can lead to arbitrary code execution.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to encompass full system compromise capabilities. An attacker could potentially execute arbitrary code with the privileges of the user running XnView Classic, leading to complete system compromise. The vulnerability is particularly concerning because .dwg files are widely used in professional environments, making exploitation likely in targeted attacks against engineering firms, architectural offices, or any organization that handles CAD drawings. The attack vector requires only that a user open or preview a maliciously crafted .dwg file, making this vulnerability highly exploitable in social engineering campaigns where users might unknowingly open compromised files.
Mitigation strategies for CVE-2017-15779 should focus on immediate patching of the XnView Classic application to version 2.44 or later, which contains the necessary fixes for the buffer overflow condition. Organizations should also implement defensive measures such as restricting file type handling for .dwg files in email gateways, web browsers, and file sharing systems. The mitigation approach aligns with ATT&CK technique T1203, which covers exploitation of remote services, and T1068, covering privilege escalation through local exploits. Network segmentation and user access controls should be enforced to limit the potential impact of successful exploitation, while security monitoring should be enhanced to detect unusual file processing activities that might indicate exploitation attempts. Additionally, organizations should consider implementing application whitelisting policies that restrict execution of untrusted .dwg files and regularly update all software components to address known vulnerabilities in the supply chain.