CVE-2017-10747 in XnView Classic
Summary
by MITRE
XnView Classic for Windows Version 2.40 allows attackers to execute arbitrary code or cause a denial of service via a crafted .rle file, related to a "User Mode Write AV starting at xnview+0x000000000037a8aa."
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Analysis
by VulDB Data Team • 07/01/2020
CVE-2017-10747 represents a critical vulnerability in XnView Classic for Windows version 2.40 that enables remote code execution or denial of service through maliciously crafted .rle files. This vulnerability manifests as a user mode write access violation within the xnview executable at address 0x000000000037a8aa, indicating a memory corruption issue that occurs during the processing of raster image files. The flaw stems from inadequate input validation and memory management when handling RLE (Run-Length Encoded) image formats, which are commonly used for compressing bitmap images. When a malicious .rle file is opened, the application fails to properly validate the file structure and size parameters, leading to buffer overflows or write operations that corrupt memory regions.
The technical exploitation of this vulnerability follows a pattern consistent with heap-based buffer overflow attacks and aligns with CWE-121, which describes heap-based buffer overflow conditions. Attackers can craft specific .rle files that, when processed by XnView Classic, trigger memory corruption that can be leveraged to execute arbitrary code with the privileges of the affected user. The vulnerability's location within user mode indicates that exploitation does not require elevated privileges, making it particularly dangerous for end-user systems. The specific address mentioned in the error suggests that the issue occurs during the decompression or rendering phase of RLE file processing, where the application attempts to write data beyond allocated memory boundaries.
This vulnerability has significant operational impact within enterprise environments where XnView Classic is commonly used for image viewing and management. The ability to execute arbitrary code through image files creates a vector for malware deployment, privilege escalation, and persistent access to compromised systems. The denial of service component means that even if code execution is not achieved, attackers can still disrupt legitimate operations by crashing the application or consuming system resources. Organizations using XnView Classic for document management, image processing, or digital asset handling face elevated risk, particularly in environments where users may inadvertently open malicious attachments or browse untrusted image repositories. The vulnerability's exploitation can occur through various attack vectors including email attachments, web downloads, or file sharing platforms, making it a widespread concern for security teams.
Mitigation strategies for CVE-2017-10747 should prioritize immediate patching of XnView Classic to version 2.41 or later, which contains the necessary fixes for memory validation and buffer handling. Organizations should implement restrictive file type handling policies that prevent automatic execution of potentially malicious image files, particularly in high-risk environments. Network-level protections including web application firewalls and content filtering systems can help block malicious .rle files before they reach user systems. Security teams should also consider implementing sandboxing techniques for image processing applications and monitoring for unusual memory access patterns that could indicate exploitation attempts. The vulnerability's classification under ATT&CK technique T1203 (Exploitation for Client Execution) and T1059 (Command and Scripting Interpreter) highlights the need for comprehensive endpoint detection and response capabilities to identify and prevent exploitation attempts. Additionally, user education programs should emphasize the dangers of opening untrusted image files and the importance of maintaining updated software versions to protect against known vulnerabilities.