CVE-2017-14557 in STDU Viewer
Summary
by MITRE
STDU Viewer 1.6.375 allows attackers to execute arbitrary code or cause a denial of service via a crafted .djvu file, related to a "User Mode Write AV starting at STDUDjVuFile!DllUnregisterServer+0x000000000000dd3f."
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Analysis
by VulDB Data Team • 11/17/2019
The vulnerability identified as CVE-2017-14557 affects STDU Viewer version 1.6.375, a document viewer application that processes djvu files. This weakness represents a critical security flaw that can be exploited to execute arbitrary code or induce denial of service conditions. The vulnerability manifests through improper handling of specially crafted .djvu files, which when processed by the application can trigger unexpected behavior in the underlying software components. The specific technical indicator points to a User Mode Write AV (Access Violation) occurring at the address STDUDjVuFile!DllUnregisterServer+0x000000000000dd3f, suggesting that the flaw exists within the dynamic link library's unregistration process. This type of vulnerability falls under the category of memory corruption issues that can lead to privilege escalation or system compromise.
The technical exploitation of this vulnerability involves crafting a malicious djvu file that triggers an access violation during the application's processing routine. When STDU Viewer attempts to handle the malformed file, the memory management system encounters an invalid write operation at the specified memory location within the DllUnregisterServer function. This memory corruption can result in the application crashing or potentially allowing an attacker to inject and execute malicious code within the application's memory space. The vulnerability demonstrates a classic buffer overflow or memory corruption pattern where insufficient input validation leads to unexpected program behavior. According to CWE classification, this vulnerability aligns with CWE-121, which deals with stack-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read conditions that can lead to memory corruption.
The operational impact of CVE-2017-14557 extends beyond simple denial of service, as it can enable remote code execution attacks. An attacker who successfully exploits this vulnerability could potentially gain control over the victim's system, especially if the application runs with elevated privileges. The attack surface is broad since djvu files are commonly used for document sharing, making this vulnerability particularly dangerous in environments where users might encounter malicious files through email attachments, web downloads, or file sharing platforms. The vulnerability also has implications for enterprise security, as it could be leveraged in targeted attacks against specific organizations or in mass phishing campaigns. From an attacker's perspective, this vulnerability fits well within the ATT&CK framework's technique T1203, which involves legitimate programs being used to execute malicious code, and T1059, which covers command and scripting interpreter usage.
Mitigation strategies for CVE-2017-14557 should include immediate application updates from the vendor to address the memory corruption flaw in the djvu file processing module. System administrators should implement strict file validation policies and consider sandboxing or virtualization of document processing applications to limit potential damage from successful exploits. Network-based protections such as intrusion detection systems should be configured to monitor for suspicious file types and unusual processing patterns that might indicate exploitation attempts. Additionally, user education regarding the risks of opening unknown or untrusted document files remains crucial. Organizations should also consider implementing application whitelisting policies that restrict execution of unauthorized applications, particularly those that handle potentially dangerous file formats like djvu. The vulnerability underscores the importance of regular security updates and proper input validation in preventing exploitation of memory corruption flaws, which aligns with security best practices outlined in NIST SP 800-171 and ISO/IEC 27001 standards for secure software development.