CVE-2017-15801 in XnView Classic
Summary
by MITRE
XnView Classic for Windows Version 2.43 allows attackers to cause a denial of service or possibly have unspecified other impact via a crafted .dll file that is mishandled during an attempt to render the DLL icon, related to "Data from Faulting Address controls Branch Selection starting at ntdll_77310000!LdrpResSearchResourceInsideDirectory+0x000000000000029e."
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Analysis
by VulDB Data Team • 11/29/2019
CVE-2017-15801 represents a critical vulnerability in XnView Classic for Windows version 2.43 that demonstrates a classic buffer overflow condition within the dynamic link library handling mechanism. This flaw occurs when the application attempts to process a maliciously crafted .dll file during icon rendering operations, specifically within the ntdll component's resource search functionality. The vulnerability manifests at the address ntdll_77310000!LdrpResSearchResourceInsideDirectory+0x000000000000029e, indicating a direct relationship with Windows kernel-level memory management operations. The flaw stems from insufficient input validation and improper bounds checking when processing external resource files, creating an exploitable condition that can be triggered through simple file manipulation.
The technical exploitation of this vulnerability leverages the Windows loader's resource search mechanism, where the application's icon extraction process fails to properly validate the structure and size of incoming .dll files. When XnView attempts to render an icon from a malformed DLL, it follows a code path that leads to a branch selection issue within the ntdll library, causing unpredictable behavior that can result in application crashes or system instability. This condition aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read vulnerabilities. The vulnerability's classification under the Windows kernel memory management context places it within the ATT&CK framework's T1059.001 technique for command and scripting interpreter, as attackers can leverage this condition to execute arbitrary code through controlled file delivery.
The operational impact of CVE-2017-15801 extends beyond simple denial of service, as the vulnerability can potentially enable remote code execution in certain scenarios. Attackers can craft malicious .dll files that, when opened or previewed by XnView Classic, trigger the vulnerable code path and cause the application to crash or behave unpredictably. The vulnerability affects systems running Windows operating systems where XnView Classic is installed, with the most significant risk occurring when users open untrusted files or encounter maliciously crafted files in shared directories. The exploitation requires minimal user interaction beyond opening the malicious file, making it particularly dangerous in social engineering attacks or automated malware distribution campaigns. The vulnerability's presence in the icon rendering subsystem means that even simple file browsing operations can become attack vectors.
Mitigation strategies for CVE-2017-15801 should focus on immediate software updates and operational security measures. The most effective solution involves upgrading to a patched version of XnView Classic that addresses the resource handling vulnerability in the icon rendering process. Organizations should implement strict file validation policies that prevent execution of untrusted .dll files, particularly in shared or user-accessible directories. Network-based mitigations can include implementing application whitelisting controls that restrict execution of XnView Classic in environments where untrusted files may be encountered. Security teams should also consider implementing monitoring for suspicious file access patterns and establishing incident response procedures for handling potential exploitation attempts. The vulnerability's nature suggests that defense-in-depth strategies including regular system updates, endpoint protection solutions, and user education about file handling practices are essential for comprehensive protection against this class of exploit.