CVE-2021-30503 in GLSL Linting Extension
Summary
by MITRE • 04/13/2021
The unofficial GLSL Linting extension before 1.4.0 for Visual Studio Code allows remote code execution via a crafted glslangValidatorPath in the workspace configuration.
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Analysis
by VulDB Data Team • 04/16/2021
The vulnerability CVE-2021-30503 affects the unofficial GLSL Linting extension for Visual Studio Code, a popular development environment used by graphics programmers and game developers working with shader languages. This extension provides linting capabilities for GLSL (OpenGL Shading Language) code, which is essential for detecting syntax errors and potential issues in shader programs. The flaw exists in versions prior to 1.4.0 and represents a critical security weakness that could be exploited by attackers to execute arbitrary code on affected systems. The vulnerability specifically targets the extension's handling of the glslangValidatorPath configuration parameter, which is used to specify the path to the glslang validator tool that performs the actual linting operations.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the extension's configuration processing logic. When users configure the glslangValidatorPath parameter in their workspace settings, the extension does not properly validate or sanitize the provided path value before executing it as a command. This creates a command injection vulnerability where an attacker can craft a malicious path value that, when processed by the extension, results in arbitrary code execution. The flaw aligns with CWE-78, which describes improper neutralization of special elements used in OS commands, and represents a classic command injection vulnerability that allows attackers to execute arbitrary system commands through untrusted input. The vulnerability is particularly dangerous because it leverages the extension's legitimate functionality to execute malicious payloads, making it difficult to detect through traditional security measures.
The operational impact of this vulnerability extends beyond simple code execution, as it affects the entire development environment of users who have installed the vulnerable extension. Attackers could exploit this vulnerability by crafting malicious workspace configurations that would be automatically executed when developers open projects containing such configurations. This scenario is particularly concerning in collaborative development environments where team members might unknowingly introduce malicious configurations or where attackers compromise shared repositories. The vulnerability could enable attackers to install malware, steal sensitive development credentials, access source code repositories, or even pivot to other systems within the development network. The attack surface is broad since developers frequently work with multiple projects and may have the extension enabled across various workspaces, potentially affecting numerous systems within an organization's infrastructure.
Mitigation strategies for CVE-2021-30503 require immediate action from affected users and organizations. The primary and most effective mitigation is to upgrade to version 1.4.0 or later of the GLSL Linting extension, which includes proper input validation and sanitization for the glslangValidatorPath parameter. Organizations should implement automated patch management processes to ensure all developers' environments are updated promptly. Additionally, security teams should conduct comprehensive vulnerability assessments to identify any systems that may have been compromised through this vulnerability. Network monitoring should be enhanced to detect unusual command execution patterns, and developers should be educated about the risks of accepting workspace configurations from untrusted sources. The vulnerability also highlights the importance of input validation in extension development and aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, demonstrating how legitimate software features can be abused for malicious purposes. Organizations should consider implementing application whitelisting policies to restrict which executables can be launched from development environments, further reducing the attack surface.