CVE-2016-1000229 in Swagger-UI
Summary
by MITRE
swagger-ui has XSS in key names
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Analysis
by VulDB Data Team • 03/16/2024
The vulnerability identified as CVE-2016-1000229 affects the swagger-ui component and represents a cross-site scripting flaw that specifically targets key names within the user interface. This vulnerability resides in the swagger-ui library which is widely used for documenting and testing restful apis. The issue manifests when the application processes and displays api key names without proper sanitization of user input, creating an avenue for malicious actors to inject malicious scripts. The vulnerability is classified under CWE-79 which specifically addresses cross-site scripting flaws in web applications. The attack vector leverages the fact that swagger-ui does not adequately validate or escape special characters in key names, allowing attackers to inject javascript code that executes in the context of other users' browsers.
The technical implementation of this vulnerability occurs within the swagger-ui rendering engine where key names are directly incorporated into html output without proper encoding or sanitization. When an api specification contains malicious key names with special characters such as angle brackets, quotes, or javascript protocols, these elements can be interpreted by web browsers as executable code rather than plain text. This allows attackers to craft api specifications that contain embedded scripts which execute when the ui renders the documentation page. The vulnerability is particularly dangerous because swagger-ui is often deployed in development environments where users may have elevated privileges or access to sensitive api endpoints. The flaw enables attackers to potentially steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users within the context of the swagger-ui application.
The operational impact of this vulnerability extends beyond simple script execution as it can facilitate more sophisticated attacks within the api documentation environment. Attackers can leverage this vulnerability to create persistent malicious payloads that remain active as long as the swagger-ui documentation page is viewed. This creates a potential for credential theft, session hijacking, or redirection to phishing sites that can target developers and administrators who regularly use the api documentation interface. The vulnerability is particularly concerning in enterprise environments where swagger-ui is used to document internal apis, as it could enable attackers to gain unauthorized access to sensitive api endpoints. According to ATT&CK framework, this vulnerability maps to T1566 which covers social engineering techniques and T1059 which involves execution through scripting languages. The attack chain typically involves crafting a malicious api specification with specially crafted key names that when rendered by swagger-ui execute the embedded javascript code in the browser context of other users.
Mitigation strategies for this vulnerability involve implementing proper input validation and output encoding mechanisms within the swagger-ui component. Organizations should ensure that all user-provided key names are sanitized before rendering in the ui interface, with special characters properly escaped or encoded to prevent script execution. The recommended approach includes implementing content security policies that restrict script execution within the swagger-ui context and ensuring that the library is updated to versions that address this specific vulnerability. Security teams should also consider implementing web application firewalls that can detect and block suspicious patterns in api specification data. Additionally, organizations should enforce strict access controls on api specification files and consider implementing automated scanning tools that can detect potentially malicious content within swagger documentation files. Regular security assessments of api documentation environments and monitoring for unusual activity patterns can help identify exploitation attempts. The vulnerability highlights the importance of input validation in web applications and demonstrates how seemingly benign components can become attack vectors when proper security measures are not implemented.