CVE-2017-9913 in XnView Classic
Summary
by MITRE
XnView Classic for Windows Version 2.40 allows remote attackers to cause a denial of service or possibly have unspecified other impact via a crafted .fpx file, related to "Data from Faulting Address controls Branch Selection starting at ntdll_77df0000!TpAllocCleanupGroup+0x00000000000003d7."
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Analysis
by VulDB Data Team • 10/23/2019
CVE-2017-9913 represents a critical vulnerability in XnView Classic for Windows version 2.40 that demonstrates a classic buffer overflow condition within the application's handling of .fpx files. This vulnerability specifically manifests when the software processes malformed file data, creating a scenario where attacker-controlled input can manipulate the program's execution flow. The flaw occurs at the ntdll_77df0000!TpAllocCleanupGroup+0x00000000000003d7 address, indicating that the issue originates from Windows native thread pool functionality and directly impacts the application's memory management routines. The vulnerability's classification as a remote attack vector means that an unauthenticated attacker can exploit this weakness without requiring local access to the target system, making it particularly dangerous in networked environments where users might inadvertently open malicious files.
The technical exploitation of this vulnerability leverages a faulting address that controls branch selection within the Windows kernel, specifically targeting the thread pool allocation mechanism. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and represents a variant of heap-based memory corruption that can be exploited through crafted input files. The attack surface expands significantly because .fpx files are commonly used for image storage and can be encountered in various digital media contexts, including email attachments, web downloads, and file sharing platforms. When a user opens a maliciously crafted .fpx file, the application's processing routine triggers an exception that allows the attacker to manipulate the program's execution path and potentially execute arbitrary code.
The operational impact of CVE-2017-9913 extends beyond simple denial of service to potentially enable full system compromise. While the vulnerability description indicates a denial of service possibility, the underlying memory corruption mechanism typically provides attackers with opportunities for more sophisticated attacks including privilege escalation and code execution. This vulnerability aligns with ATT&CK technique T1203, which covers exploitation of remote services, and demonstrates how file format processing can serve as an attack vector for broader system compromise. The attack can be executed through social engineering campaigns where users are tricked into opening seemingly legitimate image files that contain malicious payloads designed to exploit this specific flaw. Organizations using XnView Classic in enterprise environments face significant risk as this vulnerability can be leveraged to gain unauthorized access to sensitive systems and data.
Mitigation strategies for CVE-2017-9913 require immediate action including patching the vulnerable XnView Classic application to version 2.41 or later, which contains the necessary fixes for the buffer overflow condition. System administrators should implement strict file type controls and sanitize all image file uploads through content inspection mechanisms to prevent users from opening potentially malicious .fpx files. Network-based security controls including web application firewalls and email filtering systems should be configured to block .fpx file types unless absolutely necessary for business operations. The vulnerability highlights the importance of proper input validation and memory management practices in image processing applications, as recommended by OWASP Top Ten and the CERT/CC secure coding guidelines. Organizations should also consider implementing endpoint protection solutions that can detect and prevent exploitation attempts through behavioral analysis and signature-based detection mechanisms. Regular vulnerability assessments and penetration testing should be conducted to identify similar memory corruption vulnerabilities in other image processing applications and ensure comprehensive security coverage across all digital media handling systems.