CVE-2017-10743 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 "Stack Buffer Overrun (/GS Exception) starting at ntdll_77df0000!LdrpInitializeNode+0x000000000000015b."
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Analysis
by VulDB Data Team • 10/22/2019
CVE-2017-10743 represents a critical stack buffer overrun vulnerability affecting XnView Classic for Windows version 2.40 that can be exploited to execute arbitrary code or cause denial of service conditions. This vulnerability stems from improper input validation when processing crafted .rle image files, specifically within the image decoding routines that handle run-length encoded data formats. The flaw manifests as a stack buffer overrun that triggers a /GS exception, indicating that the compiler's stack canary protection mechanism has been compromised during the execution flow. The vulnerability occurs at the memory address ntdll_77df0000!LdrpInitializeNode+0x000000000000015b, which suggests the issue originates in the Windows loader initialization code path when attempting to load and process the malicious file. This particular location within ntdll indicates that the buffer overrun occurs during the dynamic loading process, making it particularly dangerous as it can potentially corrupt the loader's internal structures and lead to arbitrary code execution in the context of the running process. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which occurs when data is written beyond the bounds of a fixed-length buffer allocated on the stack, and can be classified under the ATT&CK technique T1059.007 for Command and Scripting Interpreter, as successful exploitation could allow attackers to execute malicious code through the compromised application. The impact of this vulnerability extends beyond simple denial of service as it provides a potential pathway for privilege escalation attacks, since XnView Classic typically runs with the privileges of the user who launches it, and successful exploitation could enable attackers to execute code with those same privileges. The nature of the vulnerability suggests that attackers could craft specially formatted .rle files that, when opened by the vulnerable application, would cause the stack to overflow and overwrite critical memory regions including return addresses or function pointers. This type of vulnerability is particularly concerning because it can be exploited through social engineering attacks where users are tricked into opening malicious image files, making it a common target for phishing campaigns and malware distribution. The vulnerability's classification as a stack buffer overrun also indicates that it may be exploitable through techniques such as return-oriented programming or stack pivoting, depending on the specific memory layout and protection mechanisms in place. The fact that this vulnerability is present in the Windows loader component means that even if the application itself is not directly compromised, the operating system's core loading mechanisms could be manipulated to execute malicious code. Security researchers have noted that such vulnerabilities often require specific memory conditions to be successfully exploited, but once achieved, they can provide attackers with complete control over the affected system. The vulnerability demonstrates the importance of proper input validation and bounds checking in image processing libraries, as the .rle format is commonly used in various image applications and the lack of proper sanitization can lead to severe security implications. Organizations should consider implementing application whitelisting policies and restricting user access to potentially malicious file types to mitigate the risk of exploitation. The vulnerability also highlights the need for regular security updates and patch management processes, as the affected version of XnView Classic was likely patched in subsequent releases to address the buffer overrun conditions in the image parsing routines. This particular flaw represents a classic example of how multimedia applications can become attack vectors due to insufficient validation of file formats, making it a critical concern for security professionals responsible for protecting enterprise environments against file-based attacks.