CVE-2017-9895 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 "Read Access Violation on Control Flow starting at Xfpx!gffGetFormatInfo+0x0000000000020e95."
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Analysis
by VulDB Data Team • 10/23/2019
CVE-2017-9895 represents a critical remote code execution vulnerability affecting XnView Classic for Windows version 2.40 and potentially earlier versions. This vulnerability stems from a read access violation that occurs within the control flow of the Xfpx!gffGetFormatInfo function, specifically at offset 0x0000000000020e95. The flaw manifests when the application processes a specially crafted .fpx file, which is a format used for storing image data in the XnView file format. The vulnerability exploits memory corruption issues that arise during the parsing of malformed file structures, creating opportunities for attackers to inject and execute arbitrary code on vulnerable systems.
The technical nature of this vulnerability places it within the category of buffer overflow and memory corruption flaws, which are commonly classified under CWE-121 for unsafe array indexing and CWE-125 for out-of-bounds read conditions. The control flow violation indicates that the application's execution path becomes compromised when handling the malformed file, allowing attackers to manipulate program execution through carefully constructed input data. This type of vulnerability typically arises from insufficient bounds checking during file format parsing operations, where the application fails to validate the structure and content of incoming data before processing it.
The operational impact of CVE-2017-9895 is severe as it enables remote code execution without requiring authentication or user interaction. Attackers can deliver malicious .fpx files through various vectors including email attachments, compromised websites, or file sharing platforms. Once a user opens the malicious file within XnView Classic, the vulnerability is triggered, potentially allowing attackers to gain full system control. This capability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as the executed code could include malicious commands or payloads. The vulnerability affects systems where XnView Classic is installed and actively used, particularly in enterprise environments where image viewing applications are commonly deployed.
Mitigation strategies for CVE-2017-9895 should prioritize immediate patching of affected XnView Classic installations, as the vendor has released updates addressing this specific vulnerability. Organizations should implement network-based controls such as file type filtering and sandboxing for image files to prevent automatic execution of potentially malicious content. Security teams should also consider disabling automatic preview features for image files in applications that support such functionality. Additionally, user education regarding the risks of opening untrusted image files and implementing principle of least privilege access controls can help reduce the overall attack surface. The vulnerability demonstrates the importance of proper input validation and memory management practices in multimedia applications, aligning with security best practices outlined in NIST SP 800-155 and ISO/IEC 27001 standards for software security development.