CVE-2017-14551 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 .djvu file, related to "Data from Faulting Address controls Branch Selection starting at STDUDjVuFile!DllUnregisterServer+0x000000000000d9f2."
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 11/17/2019
The vulnerability identified as CVE-2017-14551 affects STDU Viewer version 1.6.375, a document viewing application that processes djvu formatted files. This particular flaw represents a critical security issue that could potentially lead to system compromise through a carefully constructed malicious djvu file. The vulnerability manifests within the application's handling of file registration and unregistration processes, specifically within the STDUDjVuFile.dll component. The flaw occurs during the DllUnregisterServer function execution where the application fails to properly validate input data from a faulting address, creating an exploitable condition that could be leveraged by malicious actors.
The technical nature of this vulnerability aligns with common software security weaknesses that fall under CWE-122, which deals with buffer overflow conditions, and CWE-248, addressing unchecked exceptions in software. The faulting address controls branch selection within the DLL unregistration process, indicating that the application's execution flow becomes unpredictable when processing malformed input data. This type of vulnerability typically results from insufficient input validation and error handling mechanisms within the software's core components. The specific memory address mentioned in the vulnerability description suggests that the application's pointer arithmetic or memory management routines are not properly safeguarded against malformed input sequences.
From an operational perspective, this vulnerability presents significant risk to organizations that utilize STDU Viewer for document processing, particularly in environments where users might encounter untrusted or potentially malicious documents. The potential impact extends beyond simple denial of service, as the unspecified other impacts could include arbitrary code execution or privilege escalation depending on the execution context. Attackers could craft specially formatted djvu files that when opened by the vulnerable application would trigger the exploitable condition, potentially allowing them to execute malicious code on the target system. This vulnerability is particularly concerning because it affects a document viewer application that users often trust and open without suspicion.
The attack surface for this vulnerability is primarily through user interaction with document files, making social engineering attacks more effective as users might inadvertently open malicious djvu files. The exploitation process would likely involve creating a crafted djvu file that triggers the specific branch selection issue during the DLL unregistration process, potentially leading to memory corruption that could be leveraged for more serious attacks. Organizations should consider this vulnerability in their risk assessment frameworks, particularly when evaluating the security posture of systems that process untrusted document formats. The ATT&CK framework would classify this as a technique involving application execution through file format vulnerabilities, potentially leading to privilege escalation or persistent access.
Mitigation strategies should include immediate patching of affected systems, implementation of file type restrictions, and deployment of network-based intrusion detection systems to monitor for exploitation attempts. Users should be educated about the risks of opening untrusted document files and organizations should implement application whitelisting policies to prevent execution of vulnerable applications. Additionally, system administrators should consider disabling the djvu file format processing capabilities within STDU Viewer until proper patches are applied. The vulnerability highlights the importance of proper input validation and error handling in software development, particularly for applications that process external file formats, and serves as a reminder of the critical need for regular security updates and vulnerability assessments in enterprise environments.