CVE-2017-10749 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 near NULL starting at wow64!Wow64NotifyDebugger+0x000000000000001d."
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Analysis
by VulDB Data Team • 07/01/2020
CVE-2017-10749 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 near NULL, specifically occurring at wow64!Wow64NotifyDebugger+0x000000000000001d, which indicates a sophisticated memory corruption issue within the application's handling of raster image files. The flaw originates from inadequate input validation and memory management within the RLE (Run-Length Encoded) file parser, allowing attackers to craft malformed files that trigger buffer overflows or memory corruption during file processing.
The technical exploitation of this vulnerability leverages the Windows WoW64 (Windows 32-bit on Windows 64-bit) subsystem, indicating that the attack vector specifically targets the compatibility layer used by 32-bit applications running on 64-bit systems. This particular memory access violation at the debugger notification function suggests that the application fails to properly validate the boundaries of memory allocations when processing RLE format data structures. The vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios, making it a prime example of memory corruption vulnerabilities that can lead to arbitrary code execution.
From an operational perspective, this vulnerability presents a significant risk to organizations relying on XnView Classic for image processing tasks, particularly in environments where users may encounter untrusted image files from external sources. The impact extends beyond simple denial of service, as successful exploitation could allow attackers to execute malicious code with the privileges of the affected user, potentially leading to full system compromise. The vulnerability's location within the WoW64 subsystem also means that it affects both 32-bit and 64-bit Windows environments, amplifying its potential attack surface and making it particularly dangerous in enterprise environments where mixed architecture systems are common.
The attack pattern typically involves an attacker crafting a specially designed .rle file that, when opened by XnView Classic, triggers the memory corruption condition. This could occur through social engineering tactics such as email attachments, malicious websites, or compromised file sharing platforms. The vulnerability aligns with ATT&CK technique T1203, which covers "Exploitation for Client Execution" and T1059, covering "Command and Scripting Interpreter," as exploitation could lead to command execution and potentially establish persistent access. Organizations should implement strict file validation policies and avoid opening untrusted image files, while also ensuring that all systems running XnView Classic are patched to the latest version that addresses this specific memory corruption vulnerability. The recommended mitigation strategy includes immediate patch deployment, network segmentation to limit exposure, and user education to avoid opening suspicious image files, particularly those received through untrusted channels.