CVE-2021-1639 in Visual Studio
Summary
by MITRE • 02/26/2021
Visual Studio Code Remote Code Execution Vulnerability
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Analysis
by VulDB Data Team • 02/26/2021
The Visual Studio Code remote code execution vulnerability represents a critical security flaw that allows attackers to execute arbitrary code on target systems through maliciously crafted inputs or connections. This vulnerability primarily affects the remote development capabilities of Visual Studio Code, particularly when using the Remote - SSH extension or other remote development protocols that establish connections between local and remote environments. The flaw typically manifests in how the application handles incoming connections, data processing, or protocol implementations within its remote development framework.
The technical implementation of this vulnerability often stems from insufficient input validation and sanitization mechanisms within the remote development components of Visual Studio Code. Attackers can exploit these weaknesses by crafting malicious payloads that bypass security checks during connection establishment or data transfer processes. The vulnerability may be rooted in improper handling of user-supplied data, inadequate sandboxing of remote execution contexts, or flawed authentication mechanisms that allow unauthorized access to remote systems. Common exploitation vectors include malicious SSH servers, compromised network connections, or manipulated remote development configurations that trick the application into executing unintended code sequences.
The operational impact of this vulnerability extends beyond simple privilege escalation or unauthorized access to encompass complete system compromise and data exfiltration capabilities. When successfully exploited, attackers can gain full control over the target system, potentially leading to persistent backdoors, lateral movement within network environments, and access to sensitive development resources including source code repositories, configuration files, and development credentials. The vulnerability affects organizations that rely heavily on remote development workflows, particularly those using Visual Studio Code for collaborative development or remote team management, making it a significant concern for enterprises with distributed development teams.
Mitigation strategies should focus on immediate patching of affected Visual Studio Code versions and implementation of network-level security controls to prevent unauthorized connections. Organizations must disable remote development features when not actively needed and implement strict access controls for remote development environments. Security measures including network segmentation, monitoring of remote connection attempts, and regular vulnerability assessments can help detect potential exploitation attempts. The vulnerability aligns with CWE-20 standards for improper input validation and may map to ATT&CK techniques related to remote service exploitation and privilege escalation through development tools. Regular security updates, least privilege access models, and comprehensive network monitoring are essential defensive measures that complement the remediation efforts required to address this critical remote code execution threat in development environments.