CVE-2017-10745 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 "Stack Buffer Overrun (/GS Exception) starting at ntdll_77df0000!RtlProcessFlsData+0x00000000000000b0."
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Analysis
by VulDB Data Team • 10/22/2019
The vulnerability identified as CVE-2017-10745 affects XnView Classic for Windows version 2.40 and represents a critical stack buffer overrun condition that can be exploited to execute arbitrary code or cause denial of service. This flaw manifests when the application processes a specially crafted .rle file, which is a common image format used for storing raster graphics data. The vulnerability specifically occurs within the ntdll.dll module at the RtlProcessFlsData function, indicating a deep integration with Windows kernel-level memory management operations. The stack buffer overrun vulnerability stems from insufficient input validation and bounds checking during the parsing of the .rle file format, allowing attackers to overwrite adjacent memory locations on the stack.
The technical exploitation of this vulnerability leverages a stack-based buffer overflow condition that occurs when the application fails to properly validate the size of data being read from the malicious .rle file. This type of vulnerability falls under the CWE-121 category of Stack-based Buffer Overflow, which is a well-documented weakness in software security that allows attackers to overwrite stack memory locations. The attack vector is particularly dangerous because it can be triggered through normal file processing operations, requiring no special privileges or complex exploitation techniques. The specific location of the overflow at ntdll_77df0000!RtlProcessFlsData+0x00000000000000b0 indicates that the vulnerability occurs during thread-local storage data processing within the Windows operating system runtime environment, making it a particularly insidious attack surface.
From an operational impact perspective, this vulnerability presents significant risks to organizations relying on XnView Classic for image processing tasks. The ability to execute arbitrary code means that attackers could gain full system control, potentially leading to data breaches, system compromise, or lateral movement within network environments. The denial of service aspect of this vulnerability can also be leveraged to disrupt business operations, particularly in environments where image processing is critical to workflow operations. The vulnerability's exploitation requires only a single malicious file, making it an attractive target for attackers seeking to compromise systems through social engineering or automated scanning campaigns. This weakness can be mapped to ATT&CK technique T1059.007 for execution through command and scripting interpreter, as the arbitrary code execution capability could be used to launch additional malicious payloads.
The mitigation strategies for this vulnerability primarily focus on immediate software updates and patches provided by the vendor, as the flaw exists within the application's core file processing logic. System administrators should implement strict file validation policies and consider sandboxing or virtualization of image processing operations to contain potential exploitation attempts. Network-based defenses such as intrusion prevention systems can be configured to block .rle file transfers from untrusted sources, while endpoint protection solutions should be configured to monitor for suspicious file processing activities. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all systems running affected versions of XnView Classic and ensure that all instances are updated to patched versions. The vulnerability's classification as a stack buffer overrun also necessitates memory protection mechanisms such as stack canaries and address space layout randomization to be enabled on affected systems. Regular security awareness training should emphasize the risks of opening untrusted image files, particularly in environments where users may encounter malicious attachments or downloads from external sources.