CVE-2017-8368 in Sublime Text
Summary
by MITRE
Sublime Text 3 Build 3126 might allow user-assisted attackers to execute code via a crafted .mkv file. One threat model is a victim who obtains an untrusted crafted file from a remote location and issues several user-defined commands, as demonstrated by Ctrl-A, Delete, and Ctrl-Z.
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Analysis
by VulDB Data Team • 12/12/2022
The vulnerability identified as CVE-2017-8368 represents a critical code execution flaw in Sublime Text 3 version 3126 that demonstrates the dangerous intersection of media file parsing and text editor functionality. This issue arises from the application's handling of crafted .mkv files, which are multimedia container formats commonly used for video and audio content. The vulnerability exploits a fundamental security gap in how the text editor processes certain file attributes and metadata, creating an attack surface that can be leveraged by malicious actors to execute arbitrary code on affected systems. The flaw specifically manifests when the application attempts to parse and display information from the crafted media file, particularly during the file preview or metadata extraction phases.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization within Sublime Text's file processing pipeline. When a user opens or interacts with a specially crafted .mkv file, the application's internal parsing mechanisms fail to properly handle malformed or maliciously constructed file structures. This weakness allows attackers to inject code sequences that are subsequently executed within the context of the running text editor process. The vulnerability is classified as user-assisted, meaning that successful exploitation requires user interaction with the malicious file, typically through the application's interface or by triggering specific command sequences. The attack vector specifically involves the manipulation of file attributes that are processed during the editor's file handling operations, creating a code execution pathway through the application's media file parsing components.
The operational impact of CVE-2017-8368 extends beyond simple code execution, as it represents a significant threat to system integrity and user security. When successfully exploited, this vulnerability enables attackers to gain arbitrary code execution privileges on the victim's system, potentially leading to complete system compromise. The threat model described in the vulnerability assessment highlights the realistic scenario where a user unknowingly opens a malicious file from a remote source, triggering the exploitation sequence through normal user interactions such as selecting text or performing editing operations. The demonstration using Ctrl-A, Delete, and Ctrl-Z commands illustrates how standard user operations can inadvertently trigger the vulnerability, making it particularly dangerous in environments where users frequently interact with untrusted content. This vulnerability falls under the CWE-119 weakness category, which encompasses issues related to improper restriction of operations within a recognized security boundary, and aligns with ATT&CK technique T1059 for executing malicious code through command and scripting interpreters.
Mitigation strategies for CVE-2017-8368 should focus on both immediate defensive measures and long-term architectural improvements. Users should immediately update to Sublime Text version 3127 or later, which contains the necessary patches to address the vulnerability. Organizations should implement strict file access controls and user education programs to prevent accidental interaction with malicious files, particularly in environments where users may encounter untrusted content from external sources. Network administrators should consider implementing content filtering solutions that can detect and block suspicious file types, particularly multimedia files that may contain embedded malicious code. The vulnerability also underscores the importance of proper input validation and sandboxing mechanisms in applications that process external file formats, as highlighted by security best practices outlined in the OWASP Top Ten and similar industry standards. Additionally, implementing application whitelisting policies and restricting file type associations can significantly reduce the risk of exploitation, while regular security assessments of third-party applications can help identify similar vulnerabilities before they can be exploited by malicious actors.