CVE-2017-10756 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!RtlpRemoveUCRBlock+0x0000000000000046."
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Analysis
by VulDB Data Team • 10/22/2019
The vulnerability identified as CVE-2017-10756 affects XnView Classic for Windows version 2.40 and represents a critical security flaw that could enable remote attackers to execute denial of service attacks or potentially achieve arbitrary code execution. This vulnerability manifests through the improper handling of maliciously crafted .rle files during the image processing routine. The flaw specifically occurs within the ntdll.dll component of the Windows operating system where a faulting address controls branch selection, creating a pathway for attackers to manipulate program execution flow. The affected function RtlpRemoveUCRBlock within ntdll_77df0000 demonstrates how memory corruption can lead to unpredictable behavior in the application's execution path.
The technical root cause of this vulnerability lies in insufficient input validation and memory safety mechanisms within XnView's image parsing logic. When processing a specially crafted .rle file, the application fails to properly sanitize the input data, allowing malicious payloads to manipulate the control flow of the executing program. This type of vulnerability falls under the CWE-125 vulnerability category, which describes out-of-bounds read conditions where an application reads memory beyond its allocated bounds. The flaw specifically operates at the intersection of buffer over-read conditions and control flow hijacking, making it particularly dangerous for exploitation. The vulnerability's presence in ntdll.dll indicates that the issue stems from low-level Windows kernel components, suggesting that successful exploitation could potentially affect the entire operating system's stability.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it could potentially allow attackers to execute arbitrary code with the privileges of the affected application. When an attacker successfully triggers this vulnerability through a crafted .rle file, the application crashes or behaves unpredictably, which can be leveraged to cause system instability or potentially escalate privileges. This vulnerability is particularly concerning because it operates at a low level within the Windows operating system, making it difficult to detect and mitigate. The attack vector requires only that a user open a maliciously crafted image file, making it highly exploitable in social engineering scenarios where users might unknowingly execute malicious payloads through seemingly legitimate image files.
Organizations and security professionals should implement immediate mitigations to address this vulnerability by updating to the latest version of XnView Classic or applying vendor-provided patches. The mitigation strategy should include network-based restrictions that prevent users from opening unknown or untrusted image files, particularly those with .rle extensions. Additionally, implementing application whitelisting policies and restricting file execution from untrusted sources can significantly reduce the risk of exploitation. From an ATT&CK framework perspective, this vulnerability maps to technique T1059.007 for command and scripting interpreter and T1203 for Exploitation for Client Execution, as the attack requires user interaction to open malicious files and can result in code execution on the target system. Regular security assessments and vulnerability scanning should be conducted to identify systems running vulnerable versions of XnView Classic and ensure timely patch deployment across all endpoints.