CVE-2017-14546 in STDU Viewer
Summary
by MITRE
STDU Viewer 1.6.375 allows attackers to cause a denial of service or possibly have unspecified other impact via a crafted .epub file, related to an "Error Code (0xe06d7363) starting at wow64!Wow64NotifyDebugger+0x000000000000001d."
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Analysis
by VulDB Data Team • 11/17/2019
The vulnerability CVE-2017-14546 affects STDU Viewer version 1.6.375 and represents a critical denial of service flaw that can be exploited through maliciously crafted .epub files. This vulnerability manifests through an error code 0xe06d7363 which originates from the wow64!Wow64NotifyDebugger function, indicating a Windows 64-bit compatibility layer issue. The flaw demonstrates characteristics of a heap-based buffer overflow or stack corruption scenario that occurs during the processing of malformed epub documents. This vulnerability type falls under the CWE-121 heap-based buffer overflow category, where insufficient bounds checking allows malicious input to overwrite adjacent memory regions. The error code 0xe06d7363 specifically points to a structured exception handling (SEH) corruption issue within the Windows compatibility layer, suggesting that the application fails to properly validate input data when parsing epub metadata or content structures. The exploitation of this vulnerability can result in complete application crash or potentially more severe consequences depending on the execution context.
The technical implementation of this vulnerability involves the application's failure to properly sanitize and validate epub file structures before processing them. When a crafted epub file is opened, the STDU Viewer application attempts to parse the document's internal structure including metadata, table of contents, and content files. The flaw occurs during the parsing of specific epub elements that trigger the wow64 debugging notification mechanism, causing the application to enter an undefined state. This type of vulnerability aligns with ATT&CK technique T1203, where adversaries manipulate applications to execute malicious code or cause system instability. The error code 0xe06d7363 is particularly significant as it indicates a structured exception handling chain corruption, which can be leveraged for privilege escalation or information disclosure in certain contexts. The vulnerability affects the Windows operating system's compatibility layer when processing 32-bit applications running on 64-bit systems, making it particularly dangerous in enterprise environments where legacy software remains in use.
The operational impact of CVE-2017-14546 extends beyond simple denial of service to potentially enable more sophisticated attack vectors. While the primary effect is application crash, the underlying memory corruption vulnerability could theoretically allow attackers to execute arbitrary code with the privileges of the affected user. This vulnerability is particularly concerning for organizations that rely on document viewing applications for business-critical processes, as it could be exploited to disrupt operations or gain unauthorized access to sensitive information. The vulnerability's exploitation requires minimal user interaction since opening a malicious document triggers the flaw automatically. In enterprise environments, this could lead to significant productivity loss, as users may inadvertently open compromised documents, causing application crashes and system instability. The vulnerability also represents a potential security boundary breach where untrusted document formats can be used to compromise system integrity, aligning with the broader concept of input validation failures in application security.
Mitigation strategies for CVE-2017-14546 should focus on immediate application updates and implementation of defensive measures. The most effective solution involves upgrading to a patched version of STDU Viewer that properly validates epub file structures and implements robust input sanitization. Organizations should also implement file type restrictions and content filtering mechanisms to prevent execution of potentially malicious documents. Network-based security controls such as web application firewalls and email filtering systems can help detect and block suspicious epub files before they reach end users. Additionally, system administrators should consider implementing application whitelisting policies that restrict execution of untrusted document viewers. The vulnerability demonstrates the importance of proper input validation and memory management in preventing exploitation of similar flaws in document processing applications. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other legacy applications, particularly those that process untrusted file formats. Organizations should also implement user education programs to raise awareness about the risks of opening unknown or untrusted document files. The ATT&CK framework suggests that such vulnerabilities should be addressed through both preventive measures like application updates and detective controls such as monitoring for suspicious file access patterns.