CVE-2019-1486 in Visual Studio
Summary
by MITRE
A spoofing vulnerability exists in Visual Studio Live Share when a guest connected to a Live Share session is redirected to an arbitrary URL specified by the session host, aka 'Visual Studio Live Share Spoofing Vulnerability'.
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Analysis
by VulDB Data Team • 12/11/2019
The Visual Studio Live Share spoofing vulnerability represents a significant security flaw in Microsoft's collaborative development environment that enables real-time code sharing between developers. This vulnerability specifically affects the authentication and redirection mechanisms within the Live Share extension for Visual Studio and Visual Studio Code, creating a pathway for malicious session hosts to deceive guest participants through unauthorized URL redirections. The issue stems from inadequate validation of redirect destinations within the Live Share protocol, allowing session hosts with appropriate privileges to manipulate guest connections and potentially redirect them to malicious websites or phishing pages.
The technical implementation of this vulnerability resides in the improper handling of URL redirection within the Live Share extension's communication framework. When a guest joins a Live Share session, the extension establishes a connection with the session host that includes mechanisms for redirecting users to specific URLs for authentication purposes or other operational functions. The flaw occurs because the extension does not adequately verify the legitimacy or safety of these redirect URLs before executing the redirection, creating a trust relationship that can be exploited by malicious actors. This vulnerability operates at the application layer and specifically targets the trust model between session hosts and guests within the Live Share ecosystem, with the potential for escalating privileges through social engineering tactics.
The operational impact of this vulnerability extends beyond simple phishing attacks, as it enables sophisticated deception campaigns that can compromise developer credentials and sensitive code repositories. Attackers with access to a Live Share session can redirect guests to malicious domains that appear legitimate, potentially capturing authentication tokens, credentials, or other sensitive information. The vulnerability particularly affects developers working in environments where Live Share is used for collaborative coding, code reviews, or remote debugging sessions, as these scenarios often involve trust relationships that can be exploited. The implications are especially severe in enterprise environments where developers may be working with confidential source code, proprietary algorithms, or sensitive infrastructure configurations that could be compromised through such redirection attacks.
Mitigation strategies for this vulnerability require both immediate remediation and long-term architectural improvements to the Live Share extension's security model. Microsoft addressed this issue through a patch that implemented strict URL validation and verification mechanisms within the Live Share extension, ensuring that all redirect destinations are properly authenticated and validated before execution. Organizations should enforce the immediate installation of security updates and consider implementing network-level controls that monitor and restrict outbound connections from development environments. The vulnerability aligns with CWE-601, which describes URL redirection vulnerabilities, and maps to ATT&CK technique T1566, focusing on spearphishing via social engineering. Security teams should also consider implementing endpoint detection and response solutions that can monitor for suspicious URL redirection patterns within Visual Studio environments, particularly during collaborative sessions where such activities are common.
This vulnerability highlights the importance of secure communication protocols in collaborative development environments and demonstrates how seemingly benign features can become security risks when proper validation mechanisms are absent. The Live Share extension's design must now incorporate comprehensive input validation and secure redirect handling to prevent similar issues in future implementations. The remediation process required for this vulnerability emphasizes the need for continuous security assessment of development tools and extensions, particularly those that facilitate real-time collaboration and remote access scenarios where trust relationships are paramount. Organizations should also consider implementing security awareness training for developers who use collaborative tools, emphasizing the risks associated with joining untrusted sessions and the importance of verifying session host legitimacy before participating in shared development activities.