CVE-2021-28477 in Visual Studio Code
Summary
by MITRE • 04/14/2021
Visual Studio Code Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-28457, CVE-2021-28469, CVE-2021-28473, CVE-2021-28475.
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Analysis
by VulDB Data Team • 04/16/2021
The vulnerability identified as CVE-2021-28477 represents a critical remote code execution flaw within Microsoft Visual Studio Code, specifically affecting the remote development capabilities of the popular code editor. This vulnerability resides in the VS Code Remote Development extension pack, which enables developers to work with remote machines and containers through SSH, Docker, and WSL2 connections. The flaw allows attackers to execute arbitrary code on a victim's machine when they open a malicious file or project within the Visual Studio Code environment, making it particularly dangerous in enterprise and development environments where multiple users collaborate on shared codebases.
The technical root cause of this vulnerability stems from inadequate input validation and sanitization within the remote development extension's handling of file paths and remote connections. When Visual Studio Code processes remote files or directories, the system fails to properly validate user-supplied input, creating a path traversal condition that can be exploited by malicious actors. This flaw manifests when the remote development extension attempts to resolve file paths or execute commands on remote systems, allowing an attacker to inject malicious code that gets executed with the privileges of the user running Visual Studio Code. The vulnerability specifically impacts versions of Visual Studio Code prior to 1.54.3 and affects all supported operating systems including Windows, macOS, and Linux platforms.
The operational impact of CVE-2021-28477 extends far beyond simple code execution, as it provides attackers with a potential foothold for more extensive attacks within development environments. Attackers can leverage this vulnerability to gain access to sensitive source code repositories, steal development credentials, or establish persistent backdoors through the compromised Visual Studio Code instances. The vulnerability is particularly concerning in corporate environments where developers frequently use remote development features to access internal servers, cloud resources, or containerized development environments. Security researchers have noted that the exploitability of this vulnerability is high, as it requires minimal user interaction beyond opening a malicious project or file within Visual Studio Code, making it an attractive target for automated exploitation campaigns.
Organizations should immediately implement mitigations including updating Visual Studio Code to version 1.54.3 or later, which contains the necessary patches to address the input validation issues. System administrators should also consider implementing network segmentation and access controls to limit the exposure of development environments to untrusted networks. The vulnerability aligns with CWE-22 Path Traversal and CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component, and maps to ATT&CK techniques including T1059 Command and Scripting Interpreter and T1078 Valid Accounts for maintaining persistent access. Additional defensive measures include disabling the remote development features when not actively needed, implementing network monitoring to detect unusual file access patterns, and conducting regular security assessments of development environments to identify potential exploitation vectors. Organizations should also consider implementing application whitelisting policies and ensuring that developers only open projects from trusted sources to minimize the risk of exploitation.