CVE-2017-15786 in XnView Classic
Summary
by MITRE
XnView Classic for Windows Version 2.43 allows attackers to cause a denial of service or possibly have unspecified other impact via a crafted .dwg file, related to a "Read Access Violation starting at CADImage+0x00000000001a78db."
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Analysis
by VulDB Data Team • 11/29/2019
The vulnerability identified as CVE-2017-15786 represents a critical denial of service condition affecting XnView Classic for Windows version 2.43 and potentially earlier versions. This flaw manifests when the application processes specially crafted .dwg files, which are AutoCAD drawing files commonly used in engineering and architectural design. The vulnerability stems from improper input validation and memory management within the CAD image processing component of the software, specifically within the CADImage+0x00000000001a78db memory address location.
The technical root cause of this vulnerability lies in a read access violation that occurs during the parsing of maliciously constructed .dwg files. When XnView Classic attempts to load these crafted files, the application encounters a memory access error at the specified memory address, causing the program to crash or become unresponsive. This type of vulnerability falls under CWE-125, which describes out-of-bounds read conditions, and CWE-129, which covers improper validation of array indices. The flaw demonstrates characteristics of a buffer overflow condition where the application fails to properly validate the size and structure of the incoming data before attempting to process it.
From an operational perspective, this vulnerability presents significant risks to organizations relying on XnView Classic for image processing tasks. Attackers can exploit this weakness by sending malicious .dwg files to unsuspecting users, potentially causing system crashes that disrupt workflow and productivity. The unspecified other impacts mentioned in the CVE description suggest that beyond simple denial of service, there may be potential for additional security implications including arbitrary code execution or privilege escalation. This vulnerability aligns with ATT&CK technique T1203, which covers exploitation of software vulnerabilities for system compromise, and T1499, which addresses network denial of service attacks.
The impact extends beyond individual user systems to enterprise environments where XnView Classic might be used for batch processing or automated image handling. Organizations using this software in production environments face risks of service disruption, particularly in scenarios where automated workflows depend on image processing capabilities. The vulnerability affects the core functionality of the application and could be exploited in targeted attacks against specific users or systems. Security teams should consider this vulnerability as part of broader threat modeling exercises, particularly in environments where users may encounter untrusted image files or where file sharing occurs across network boundaries. The memory access violation represents a fundamental flaw in the application's error handling and input validation mechanisms, making it particularly dangerous in automated processing scenarios where multiple files are processed sequentially.
Organizations should immediately implement mitigations including updating to the latest version of XnView Classic where this vulnerability has been addressed, implementing network segmentation to limit exposure, and deploying application whitelisting policies to prevent execution of vulnerable software. Additionally, users should be educated about the risks of opening untrusted .dwg files and organizations should consider implementing file validation processes for incoming image files. The vulnerability demonstrates the importance of proper input validation and memory management in image processing applications, particularly those handling complex file formats like .dwg files that contain extensive metadata and structured data elements.