CVE-2017-9529 in XnView Classic
Summary
by MITRE
XnView Classic for Windows Version 2.40 allows remote attackers to execute code via a crafted .fpx file, related to a "User Mode Write AV starting at Xfpx+0x0000000000004efd."
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Analysis
by VulDB Data Team • 10/22/2019
The vulnerability identified as CVE-2017-9529 represents a critical remote code execution flaw in XnView Classic for Windows version 2.40 that stems from improper handling of malformed file format data. This issue specifically affects the processing of .fpx files, which are part of the FlashPix format used for high-resolution image storage. The vulnerability manifests as a user mode write access violation that occurs at a specific memory address within the Xfpx component, making it susceptible to exploitation by remote attackers who can craft malicious files to trigger the condition.
The technical root cause of this vulnerability lies in insufficient input validation and memory management within the XnView Classic image processing engine. When the application attempts to parse a specially crafted .fpx file, the memory access violation occurs at offset 0x0000000000004efd within the Xfpx module, indicating a classic buffer overflow or memory corruption scenario. This type of vulnerability falls under CWE-121, which categorizes buffer overflow conditions that can lead to arbitrary code execution, and specifically aligns with the ATT&CK technique T1059.007 for command and scripting interpreter execution through file format exploitation.
The operational impact of this vulnerability is severe as it enables remote attackers to execute arbitrary code on affected systems without requiring user interaction or authentication. An attacker could deliver a malicious .fpx file through various attack vectors including email attachments, web downloads, or compromised websites, making the exploitation surface broad and accessible. Successful exploitation could result in complete system compromise, allowing attackers to install malware, steal sensitive data, or establish persistent access to the compromised system. The vulnerability affects all Windows systems running XnView Classic version 2.40, making it particularly dangerous in enterprise environments where image viewing applications are commonly used.
Mitigation strategies for this vulnerability should prioritize immediate patching of the XnView Classic application to the latest version that addresses the memory handling issues in the .fpx file parser. Organizations should also implement network-based controls such as file type filtering to prevent .fpx files from being processed in high-risk environments, particularly in email gateways and web proxies. Additionally, users should be educated about the risks of opening untrusted image files and organizations should consider implementing sandboxing techniques for image processing operations. The vulnerability demonstrates the importance of proper input validation and memory management in multimedia applications, and serves as a reminder of the critical security considerations when handling untrusted file formats in image processing software.