CVE-2017-9901 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 "Data from Faulting Address controls subsequent Write Address starting at Xfpx!gffGetFormatInfo+0x000000000002bfd5."
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Analysis
by VulDB Data Team • 10/23/2019
The vulnerability identified as CVE-2017-9901 affects XnView Classic for Windows version 2.40 and represents a critical remote code execution flaw that can be exploited through maliciously crafted .fpx files. This vulnerability stems from improper input validation within the image processing pipeline, specifically when handling Fast Picture Exchange format files. The flaw occurs at the address Xfpx!gffGetFormatInfo+0x000000000002bfd5, indicating a memory corruption issue that allows attackers to manipulate the program's execution flow. The vulnerability is particularly dangerous because it enables remote attackers to execute arbitrary code on affected systems without requiring any user interaction, making it an ideal candidate for automated exploitation campaigns.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-787, which covers out-of-bounds write operations. The flaw manifests when the application processes malformed .fpx files that contain specially crafted data structures designed to overwrite memory locations beyond the intended buffer boundaries. This memory corruption directly impacts the program's control flow, allowing attackers to redirect execution to malicious code. The vulnerability's location within the Xfpx!gffGetFormatInfo function suggests that the issue originates from how the application handles format information parsing for Fast Picture Exchange files, where insufficient bounds checking permits unauthorized memory access patterns.
From an operational perspective, this vulnerability presents significant risk to organizations that may unknowingly process potentially malicious image files through XnView Classic. The remote code execution capability means that attackers can compromise systems simply by enticing users to open crafted image files, potentially through email attachments, web downloads, or file sharing platforms. The attack vector does not require user interaction beyond opening the file, making it particularly effective for social engineering campaigns. Additionally, the vulnerability affects a widely used image viewing application, increasing the potential attack surface and exploitation success rate. The flaw can lead to complete system compromise, allowing attackers to install malware, steal sensitive data, or establish persistent backdoors.
Mitigation strategies for CVE-2017-9901 should include immediate application updates from the vendor, as the issue was addressed in subsequent versions of XnView Classic. Organizations should implement network-level restrictions to prevent access to potentially malicious image files, particularly in environments where XnView Classic is used. Security teams should deploy endpoint protection solutions with file type validation and behavior monitoring capabilities to detect anomalous file processing activities. Additionally, user education programs should emphasize the dangers of opening unknown image files from untrusted sources. The vulnerability also highlights the importance of input validation and memory safety practices in image processing libraries, as outlined in the software security principles of the OWASP Top Ten and the MITRE ATT&CK framework's defense evasion techniques. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other image processing applications within the organization's infrastructure.