CVE-2017-15788 in XnView Classic
Summary
by MITRE
XnView Classic for Windows Version 2.43 allows attackers to execute arbitrary code or cause a denial of service via a crafted .dwg file, related to a "User Mode Write AV starting at CADImage+0x0000000000002d83."
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Analysis
by VulDB Data Team • 11/29/2019
CVE-2017-15788 represents a critical vulnerability in XnView Classic for Windows version 2.43 that exposes users to potential arbitrary code execution or denial of service attacks through maliciously crafted .dwg files. This vulnerability manifests as a user mode write access violation within the CADImage component at offset 0x0000000000002d83, indicating a memory corruption issue that occurs during the processing of AutoCAD drawing files. The flaw stems from inadequate input validation and memory management within the image parsing functionality, specifically when handling the complex data structures inherent in .dwg file formats used by AutoCAD and other CAD applications.
The technical nature of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-125, which addresses out-of-bounds read vulnerabilities. Attackers can exploit this weakness by crafting specially designed .dwg files that trigger memory corruption when XnView attempts to parse and display these images. The vulnerability occurs during the rendering process where the application fails to properly validate the boundaries of memory allocations, leading to write operations that exceed allocated buffer limits. This type of flaw falls under the ATT&CK technique T1203, specifically "Exploitation for Client Execution," where adversaries leverage application vulnerabilities to execute malicious code on target systems.
The operational impact of this vulnerability is significant as it allows attackers to execute arbitrary code with the privileges of the user running XnView, potentially leading to complete system compromise. The denial of service aspect can be equally damaging, as it can cause the application to crash repeatedly, disrupting legitimate user activities and potentially serving as a vector for persistent availability attacks. Since XnView is commonly used for image viewing and management, the attack surface is broad, encompassing users who might unknowingly open malicious files from email attachments, web downloads, or shared network drives. The vulnerability is particularly dangerous in enterprise environments where users may have elevated privileges or where the application is used in automated workflows.
Mitigation strategies should include immediate patching of XnView Classic to version 2.44 or later, which contains the necessary memory validation fixes. Organizations should also implement strict file type filtering and sandboxing mechanisms to prevent automatic execution of potentially malicious files. Network administrators should consider implementing content filtering solutions that can detect and block .dwg files from untrusted sources, particularly those that might contain embedded malicious code. Users should be educated about the risks of opening files from unknown or untrusted sources, and security teams should monitor for exploitation attempts through network traffic analysis and endpoint detection systems. Additionally, implementing application whitelisting policies that restrict execution of untrusted image processing applications can provide an additional layer of defense against this type of vulnerability exploitation.