CVE-2020-1416: Azure Storage Explorer Privilege Escalation

CVE-2020-1416 Overview

An elevation of privilege vulnerability exists in Visual Studio and Visual Studio Code when they load software dependencies. This vulnerability, classified as CWE-269 (Improper Privilege Management), allows attackers to potentially execute code with elevated privileges by exploiting the way these development environments handle software dependency loading.

Critical Impact

Attackers can leverage this vulnerability to elevate privileges through malicious software dependencies, potentially gaining unauthorized access to system resources and executing arbitrary code with elevated permissions in development environments.

Affected Products

• Microsoft Visual Studio 2017
• Microsoft Visual Studio 2019
• Microsoft Visual Studio Code
• Microsoft Azure Storage Explorer
• Microsoft TypeScript

Discovery Timeline

• 2020-07-14 - CVE-2020-1416 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2020-1416

Vulnerability Analysis

This elevation of privilege vulnerability stems from improper handling of software dependencies in Microsoft's development tools. When Visual Studio or Visual Studio Code loads dependencies, the applications fail to properly validate and restrict the privileges under which these dependencies execute. This creates an attack surface where a malicious dependency can be crafted to execute with higher privileges than intended.

The vulnerability requires user interaction to exploit, typically involving a developer opening a malicious project or installing a compromised extension. Once triggered, the attacker can leverage the trust relationship between the development environment and its dependencies to escalate privileges on the affected system.

Root Cause

The root cause lies in improper privilege management (CWE-269) within the dependency loading mechanism of Visual Studio and Visual Studio Code. The applications do not adequately enforce privilege separation when loading external software components, allowing dependencies to inherit or acquire elevated privileges during the loading process. This architectural flaw enables attackers to abuse the dependency chain to execute code with privileges beyond what should be permitted.

Attack Vector

The attack vector is network-based, requiring user interaction to initiate the exploit. An attacker could craft a malicious Visual Studio project, VS Code extension, or manipulated package that contains specially crafted dependencies designed to exploit this vulnerability.

The attack flow typically involves:

1. An attacker creates or compromises a software package, extension, or project file
2. The victim downloads and opens the malicious project or installs the compromised extension
3. When Visual Studio or VS Code loads the software dependencies, the malicious payload executes
4. The payload leverages the privilege management flaw to escalate privileges
5. The attacker gains elevated access to the system, potentially compromising confidentiality, integrity, and availability

Detection Methods for CVE-2020-1416

Indicators of Compromise

• Unexpected processes spawned by Visual Studio or VS Code with elevated privileges
• Unusual dependency loading behavior or unfamiliar packages being loaded at startup
• Anomalous network connections initiated by development environment processes
• Modified or new files in Visual Studio/VS Code extension directories with suspicious timestamps

Detection Strategies

• Monitor process creation events for child processes of devenv.exe (Visual Studio) or code.exe (VS Code) executing with unexpected privilege levels
• Implement application whitelisting to detect unauthorized extensions or dependencies
• Deploy endpoint detection solutions capable of identifying privilege escalation attempts
• Review installed extensions and dependencies for unauthorized or unverified packages

Monitoring Recommendations

• Enable detailed logging for Visual Studio and VS Code extension installations
• Implement file integrity monitoring on development environment installation directories
• Configure SIEM alerts for anomalous privilege escalation patterns associated with development tools
• Regularly audit installed extensions against approved organizational baselines

How to Mitigate CVE-2020-1416

Immediate Actions Required

• Apply Microsoft security updates for all affected Visual Studio and VS Code installations immediately
• Review and remove any untrusted or unnecessary extensions from development environments
• Restrict users from installing extensions without administrative approval
• Isolate development environments from production networks where possible

Patch Information

Microsoft has released security patches addressing this vulnerability. Organizations should apply the updates available through the Microsoft Security Advisory CVE-2020-1416. The patches are available for Visual Studio 2017, Visual Studio 2019, Visual Studio Code, Azure Storage Explorer, and TypeScript.

Update Visual Studio through the Visual Studio Installer, and VS Code through the built-in update mechanism or by downloading the latest version from the official Microsoft website.

Workarounds

• Implement strict extension approval policies limiting installations to verified, trusted sources only
• Run development environments in sandboxed or virtualized environments to contain potential privilege escalation
• Disable automatic extension updates and manually review each update before installation
• Apply the principle of least privilege, ensuring developers do not run IDEs with administrator rights

# Configuration example
# Verify Visual Studio installation and check for pending updates
# Run from Visual Studio Developer Command Prompt
vs_installer.exe update --passive --norestart

# For VS Code, verify installed extensions
code --list-extensions

# Remove suspicious extensions
code --uninstall-extension <suspicious-extension-id>