CVE-2017-8387 in STDU Viewer
Summary
by MITRE
STDU Viewer version 1.6.375 might allow user-assisted attackers to execute code via a crafted file. One threat model is a victim who obtains an untrusted crafted file from a remote location and issues several user-defined commands including Ctrl-+ commands.
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Analysis
by VulDB Data Team • 10/22/2019
The vulnerability identified as CVE-2017-8387 affects STDU Viewer version 1.6.375 and represents a critical code execution flaw that can be exploited through crafted malicious files. This vulnerability falls under the category of buffer overflow and arbitrary code execution, which are fundamental security concerns that can lead to complete system compromise when exploited successfully. The vulnerability specifically targets the file parsing functionality of the viewer application, where improper input validation allows attackers to craft specially formatted files that trigger unexpected behavior in the software's processing pipeline.
The technical flaw manifests when the STDU Viewer application processes untrusted files without adequate sanitization of input data. Attackers can create malicious files that contain specially crafted data structures or commands that, when processed by the viewer, cause the application to execute arbitrary code on the victim's system. The vulnerability is particularly concerning because it requires only a single user interaction to be successful, as the attacker can deliver the malicious file through remote channels and then prompt the victim to open it. The specific mention of Ctrl-+ commands indicates that the vulnerability may be exploitable through keyboard shortcuts or command sequences that are typically used for navigation or document manipulation within the viewer.
The operational impact of this vulnerability extends beyond simple code execution, as it can lead to complete system compromise when attackers leverage the ability to execute arbitrary commands. The threat model described in the CVE indicates that attackers can deliver malicious files through remote locations, suggesting that the vulnerability could be exploited in phishing campaigns, malicious file sharing, or other social engineering attacks. The user-assisted nature of the attack means that while the attacker doesn't need to be present during the exploitation process, they must somehow convince the victim to interact with the crafted file. This makes the vulnerability particularly dangerous in enterprise environments where users may encounter malicious files through email attachments, file downloads, or shared network drives.
Security professionals should consider this vulnerability in the context of the CWE taxonomy, specifically CWE-121, which deals with stack-based buffer overflow conditions, and CWE-78, which addresses OS command injection vulnerabilities. The ATT&CK framework would categorize this vulnerability under T1059, which involves command and scripting interpreter, as the exploitation likely involves executing commands through the viewer application. Organizations should implement immediate mitigations including updating to patched versions of STDU Viewer, implementing strict file validation policies, and educating users about the risks of opening untrusted files from remote sources. Network-level protections such as email filtering, web proxies, and file integrity checking mechanisms should also be deployed to reduce the attack surface and prevent successful exploitation attempts.