CVE-2013-5042 in ASP .NET SignalR
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Microsoft ASP.NET SignalR 1.1.x before 1.1.4 and 2.0.x before 2.0.1, and Visual Studio Team Foundation Server 2013, allows remote attackers to inject arbitrary web script or HTML via crafted Forever Frame transport protocol data, aka "SignalR XSS Vulnerability."
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Analysis
by VulDB Data Team • 12/25/2024
The CVE-2013-5042 vulnerability represents a critical cross-site scripting flaw affecting Microsoft ASP.NET SignalR versions 1.1.x prior to 1.1.4 and 2.0.x prior to 2.0.1, along with Visual Studio Team Foundation Server 2013. This vulnerability operates through the Forever Frame transport protocol mechanism that SignalR employs for real-time communication between client and server applications. The flaw specifically manifests when the system processes crafted data within the Forever Frame transport channel, creating an avenue for remote attackers to execute malicious web scripts or HTML code within the context of victim users' browsers. This type of vulnerability falls under CWE-79 which categorizes cross-site scripting flaws as a result of inadequate input validation and output encoding practices.
The technical exploitation of this vulnerability occurs when SignalR's Forever Frame transport protocol fails to properly sanitize or encode user-supplied data before rendering it within web pages. Attackers can craft malicious payloads that exploit the lack of proper input validation in the transport layer, specifically targeting the way SignalR handles data transmission through persistent HTTP connections. The vulnerability is particularly concerning because it operates at the transport protocol level rather than the application layer, meaning that even legitimate SignalR applications using the Forever Frame transport mechanism could become vectors for XSS attacks. The attack surface extends to any application utilizing SignalR's streaming capabilities, particularly those that rely on the older versions of the framework where this security gap existed.
The operational impact of this vulnerability is significant for organizations using affected versions of SignalR or Visual Studio Team Foundation Server 2013. Remote attackers could potentially execute malicious scripts in the context of authenticated users, leading to session hijacking, credential theft, or data exfiltration. The vulnerability affects not just individual web applications but entire development environments that might be using SignalR for real-time collaboration features, chat systems, or live updating dashboards. Given that SignalR was commonly used in enterprise environments for building interactive web applications, the potential for widespread exploitation exists across multiple organizational systems. This vulnerability also aligns with ATT&CK technique T1566 which involves the use of malicious content to establish initial access or maintain persistence within target environments.
Organizations should prioritize immediate patching of affected systems, upgrading to SignalR versions 1.1.4 or later for 1.1.x releases, and 2.0.1 or later for 2.0.x releases. Additionally, implementing proper input validation and output encoding mechanisms can serve as temporary mitigations while patches are deployed. Security teams should also consider monitoring for unusual traffic patterns in applications using SignalR's transport protocols and implementing web application firewalls to detect and block malicious payload delivery. The vulnerability underscores the importance of maintaining up-to-date security practices and highlights the need for thorough security testing of real-time communication frameworks that handle user data through persistent connections.