CVE-2017-9908 in XnView Classic
Summary
by MITRE
XnView Classic for Windows Version 2.40 allows remote attackers to cause a denial of service or possibly have unspecified other impact via a crafted .fpx file, related to a "Read Access Violation starting at Xfpx+0x000000000000d6da."
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Analysis
by VulDB Data Team • 10/23/2019
CVE-2017-9908 represents a critical vulnerability in XnView Classic for Windows version 2.40 that exposes the application to remote code execution and denial of service attacks through malformed file handling. This vulnerability specifically targets the FPX file format processing within the image viewer application, creating a dangerous condition where a specially crafted .fpx file can trigger a read access violation at a specific memory address. The flaw manifests as a memory corruption issue that occurs during the parsing of FPX file headers and metadata, allowing attackers to manipulate the application's memory management routines. The vulnerability is classified under CWE-125 as an out-of-bounds read condition, which is particularly dangerous because it can lead to arbitrary code execution when the application attempts to access memory beyond the allocated buffer boundaries. This type of vulnerability falls within the ATT&CK technique T1203 - Exploitation for Client Execution, where adversaries leverage application vulnerabilities to execute malicious code in the context of the victim's application process.
The technical exploitation of this vulnerability requires an attacker to prepare a malicious FPX file that contains crafted data structures designed to trigger the memory access violation at the specific offset 0x000000000000d6da within the Xfpx component. When the vulnerable XnView Classic application attempts to load this crafted file, the application's memory management system encounters a corrupted data structure that causes the program to crash or potentially execute unintended code. The vulnerability stems from insufficient bounds checking during the parsing of FPX file metadata, particularly in how the application handles the file's header information and embedded image data structures. This lack of proper input validation creates a pathway for attackers to manipulate the application's execution flow, potentially leading to complete system compromise. The vulnerability is particularly concerning because it can be triggered through simple file opening operations, making it accessible to attackers who might trick users into opening malicious files through social engineering or phishing campaigns.
The operational impact of CVE-2017-9908 extends beyond simple denial of service conditions, as the vulnerability can potentially allow remote code execution with the privileges of the user running the vulnerable application. This makes it a significant threat in enterprise environments where users may inadvertently open malicious files from untrusted sources, potentially leading to complete system compromise. The vulnerability affects all users running XnView Classic version 2.40 or earlier, regardless of their security awareness level, as the exploitation does not require specialized knowledge or complex attack vectors. Organizations using this image viewer for document management, digital asset handling, or general image viewing operations face substantial risk from this vulnerability, particularly in environments where users may receive files from external sources or where automated file processing systems might encounter malicious files. The vulnerability's impact is amplified by the fact that FPX files are commonly used in digital imaging workflows, making the attack surface larger than initially apparent.
Mitigation strategies for CVE-2017-9908 should prioritize immediate patching of the vulnerable XnView Classic application to version 2.41 or later, which contains the necessary fixes for the memory access violation issue. System administrators should implement strict file validation policies that prevent automatic execution of potentially malicious files, particularly in enterprise environments where users may encounter untrusted file formats. Network-level protections such as email filtering and web application firewalls can help prevent the delivery of malicious FPX files to end users, while endpoint protection solutions should be configured to monitor for suspicious file access patterns. Users should be educated about the risks of opening files from untrusted sources and trained to recognize potential social engineering attempts that might lead to exploitation of this vulnerability. Organizations should also consider implementing application whitelisting policies that restrict the execution of image viewing applications to known good versions, and establish regular vulnerability assessment procedures to identify and remediate similar issues in other software applications. The vulnerability highlights the importance of maintaining up-to-date software versions and implementing comprehensive security controls to protect against file format-based exploitation techniques.