CVE-2017-10769 in XnView Classic
Summary
by MITRE
XnView Classic for Windows Version 2.40 might allow attackers to cause a denial of service or possibly have unspecified other impact via a crafted .rle file, related to "Data from Faulting Address controls Branch Selection starting at ntdll_77df0000!memcmp+0x0000000000000018" (without RPC initialization).
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Analysis
by VulDB Data Team • 10/22/2019
CVE-2017-10769 represents a critical vulnerability in XnView Classic for Windows version 2.40 that demonstrates a classic buffer overflow condition within the image processing pipeline. This vulnerability specifically manifests when the application processes crafted .rle files, which are Run-Length Encoded image format files commonly used for compressing bitmap images. The flaw occurs during the memcmp function execution within the ntdll library, where faulting address data directly influences branch selection logic, creating a condition where attacker-controlled input can manipulate program flow. The vulnerability lacks RPC initialization requirements, making it particularly dangerous as it can be exploited through simple file manipulation without complex network infrastructure. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and represents a direct exploitation of memory corruption principles that have been extensively documented in cybersecurity literature. The attack vector is particularly concerning because it requires no specialized network access or complex setup, as the vulnerability is triggered simply by opening a maliciously crafted file within the vulnerable application.
The technical implementation of this vulnerability demonstrates how image parsing libraries can become attack surfaces when proper input validation and bounds checking are not implemented. When XnView Classic processes the crafted .rle file, the malformed data structure causes the memcmp function to receive unexpected parameters that result in a faulting address being used to control program branching. This creates a scenario where an attacker can manipulate the execution flow of the application through carefully constructed input data, potentially leading to denial of service conditions or more severe impacts. The ntdll_77df0000!memcmp+0x0000000000000018 reference indicates the precise memory location where the vulnerability occurs, suggesting a well-defined exploitation point that attackers can target. This vulnerability operates at the intersection of image processing and memory management, where the application's failure to properly validate image file structures allows malicious input to corrupt the application's memory space and potentially execute arbitrary code. The lack of RPC initialization means the attack can be executed locally or remotely through file sharing mechanisms, expanding the potential attack surface significantly.
The operational impact of CVE-2017-10769 extends beyond simple denial of service, as it represents a potential pathway for more sophisticated attacks within the context of the ATT&CK framework's initial access and execution phases. When an attacker successfully exploits this vulnerability, they can potentially cause the application to crash or behave unpredictably, leading to service disruption for legitimate users. However, the more serious implications arise from the possibility of code execution, which would allow attackers to gain unauthorized access to systems running vulnerable versions of XnView Classic. This vulnerability particularly affects environments where users frequently open images from untrusted sources, such as email attachments, web downloads, or file sharing platforms. The vulnerability's impact is amplified because XnView Classic is a widely used image viewer application, meaning that successful exploitation could affect numerous end-user systems. Organizations that rely on image viewing applications for document management or user productivity are particularly at risk, as the exploitation can occur without user awareness, potentially leading to persistent access or data exfiltration. The vulnerability's exploitation aligns with ATT&CK technique T1203, which describes the use of legitimate user programs for execution purposes.
Mitigation strategies for CVE-2017-10769 must address both immediate operational concerns and long-term security improvements. The primary recommendation involves upgrading to a patched version of XnView Classic, as the vulnerability was resolved in subsequent releases through improved input validation and memory management. System administrators should implement strict file validation policies, particularly for image files received from external sources, and consider deploying sandboxing techniques when processing potentially malicious files. Network-level protections should include filtering of .rle file extensions and implementing application whitelisting to prevent execution of vulnerable versions. Additionally, users should be educated about the risks of opening image files from untrusted sources and encouraged to verify file integrity before opening. The vulnerability serves as a reminder of the importance of proper input validation in image processing libraries and the need for comprehensive security testing of multimedia applications. Security teams should also consider implementing intrusion detection systems that can identify suspicious file processing patterns and monitor for exploitation attempts. Regular security assessments of image viewing applications and other multimedia software should be conducted to identify similar vulnerabilities in the broader software ecosystem, as this type of memory corruption vulnerability is not unique to XnView Classic and can be found in various image processing libraries across different platforms.