CVE-2017-8282 in XnView Classic
Summary
by MITRE
XnView Classic for Windows Version 2.40 allows user-assisted remote attackers to execute code via a crafted .mov file that is mishandled during the opening of a directory in "Browser" mode, because of a "User Mode Write AV near NULL" in XnView.exe.
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Analysis
by VulDB Data Team • 07/01/2020
The vulnerability CVE-2017-8282 represents a critical remote code execution flaw in XnView Classic for Windows version 2.40 that demonstrates a classic buffer overflow condition in memory handling. This vulnerability specifically manifests when the application processes a maliciously crafted .mov file within its Browser mode functionality, creating a dangerous scenario where legitimate user interaction becomes a vector for malicious code execution. The flaw resides in the application's improper handling of multimedia file metadata during directory traversal operations, where the software fails to properly validate file structures before attempting to parse them.
The technical root cause of this vulnerability stems from a user mode write access violation near NULL pointer in the XnView.exe process, which constitutes a classic null pointer dereference scenario. This type of vulnerability falls under CWE-476 which specifically addresses NULL pointer dereference conditions in software applications. The flaw occurs during the directory browsing functionality when the application attempts to open a directory containing the malicious .mov file, triggering an improper memory access pattern that allows attackers to manipulate the execution flow of the process. The vulnerability is particularly dangerous because it requires only user-assisted remote exploitation, meaning an attacker can convince a user to open a malicious file through social engineering or other means, making the attack surface significantly larger than purely automated exploits.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with a complete compromise of the affected system. When successfully exploited, the vulnerability allows remote attackers to execute arbitrary code with the privileges of the user running XnView, potentially leading to full system compromise, data exfiltration, or establishment of persistent backdoors. The attack vector is particularly concerning because it leverages the application's legitimate file browsing functionality, making it difficult for security controls to distinguish between benign and malicious activity. This vulnerability also demonstrates the broader risk associated with multimedia processing libraries and the complex parsing requirements they impose on software applications, as the .mov file format contains numerous potential attack vectors due to its complex structure and metadata handling requirements.
Mitigation strategies for this vulnerability should focus on immediate software updates and patches from the vendor, as well as network-level controls to prevent access to potentially malicious file types. Organizations should implement strict file type filtering and validation mechanisms, particularly for multimedia files that are commonly used in social engineering attacks. The vulnerability also highlights the importance of input validation and memory safety practices in software development, particularly for applications that process untrusted data from external sources. Security teams should consider implementing application whitelisting policies to restrict execution of vulnerable software versions and monitor for unusual file access patterns that might indicate exploitation attempts. This vulnerability aligns with ATT&CK technique T1059.007 for remote code execution and T1203 for exploitation for privilege escalation, emphasizing the need for comprehensive endpoint security controls to prevent exploitation of such memory corruption vulnerabilities.