CVE-2017-10740 in XnView Classic
Summary
by MITRE
XnView Classic for Windows Version 2.40 allows attackers to execute arbitrary code or cause a denial of service via a crafted .rle file, related to a "User Mode Write AV starting at ntdll_77df0000!RtlRbInsertNodeEx+0x000000000000002d."
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 07/01/2020
CVE-2017-10740 represents a critical heap-based buffer overflow vulnerability affecting XnView Classic for Windows version 2.40. This vulnerability stems from insufficient input validation when processing specially crafted .rle files, which are run-length encoded image format files commonly used for storing bitmap images. The flaw manifests during the parsing of maliciously constructed RLE data structures, leading to memory corruption that can be exploited by remote attackers to execute arbitrary code or induce system crashes.
The technical root cause of this vulnerability lies in the improper handling of user-supplied data within the image processing pipeline. When XnView Classic attempts to parse the malicious .rle file, the application fails to properly validate the bounds of memory allocations, resulting in a write access violation within the Windows ntdll.dll module. Specifically, the error occurs at the RtlRbInsertNodeEx function within ntdll_77df0000, indicating that the vulnerability involves a heap-based buffer overflow that corrupts the Red-Black tree data structure used internally by the Windows kernel for memory management operations. This type of vulnerability falls under CWE-121, heap-based buffer overflow, and represents a classic example of unsafe memory handling practices.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with multiple attack vectors for system compromise. Successful exploitation can result in arbitrary code execution with the privileges of the affected user, potentially leading to complete system takeover. Additionally, the vulnerability can be leveraged to cause denial of service conditions, rendering the application unusable and potentially affecting system stability. Attackers can craft malicious .rle files that trigger the vulnerability through various attack vectors including email attachments, web downloads, or file sharing platforms, making this a particularly dangerous flaw in a widely used image viewing application.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as exploitation may involve executing malicious code through compromised applications. The vulnerability also maps to T1203 for exploitation for privilege escalation, as the heap corruption can potentially be leveraged to gain elevated privileges. Organizations using XnView Classic should implement immediate mitigations including application whitelisting, restricting file type handling, and deploying network-based intrusion detection systems to monitor for exploitation attempts. The recommended remediation involves updating to a patched version of XnView Classic or implementing strict input validation controls to prevent processing of untrusted .rle files. Security teams should also consider implementing sandboxing mechanisms and regular vulnerability assessments to identify similar memory corruption flaws in other image processing applications that may be susceptible to similar exploitation techniques.