CVE-2017-18176 in Sitefinity
Summary
by MITRE
Progress Sitefinity 9.1 has XSS via file upload, because JavaScript code in an HTML file has the same origin as the application's own code. This is fixed in 10.1.
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Analysis
by VulDB Data Team • 02/06/2023
Progress Sitefinity version 9.1 contains a cross-site scripting vulnerability that arises from improper validation of file uploads within the content management system. The flaw occurs when users can upload HTML files that contain malicious javascript code, which executes within the same origin context as the application itself. This vulnerability stems from the application's failure to properly sanitize or validate the content of uploaded files, particularly those with html extensions that may contain embedded script tags. The security issue is classified under the CWE-79 category for cross-site scripting, which represents one of the most prevalent and dangerous web application vulnerabilities. Attackers can exploit this weakness by uploading crafted html files containing malicious javascript that executes in the context of authenticated users, potentially leading to session hijacking, data theft, or further exploitation of the application.
The technical implementation of this vulnerability allows malicious actors to leverage the same origin policy in a way that bypasses normal security boundaries. When an HTML file containing javascript is uploaded to the Sitefinity system, the application treats it as legitimate content and executes the embedded script within the user's browser session. This creates an environment where the malicious code can access cookies, local storage, and other session data that would normally be protected by the browser's security model. The vulnerability is particularly dangerous because it occurs during file upload operations, which are common administrative tasks that authenticated users perform regularly. The same origin policy that normally protects web applications becomes a vector for attack when the application itself serves content that contains malicious scripts, as the browser considers the uploaded content to be part of the same trusted domain.
The operational impact of CVE-2017-18176 extends beyond simple script execution to potentially enable more sophisticated attacks against the Sitefinity installation. An attacker who successfully exploits this vulnerability can establish persistent access to the application, monitor user activities, steal authentication tokens, and potentially escalate privileges within the system. This vulnerability aligns with ATT&CK technique T1059.007 for scripting, specifically targeting the execution of malicious javascript in web browsers. The attack surface is broad since any user with upload privileges can potentially exploit this weakness, making it particularly dangerous in environments where multiple administrators have access to the content management system. The vulnerability represents a critical security gap in the application's file handling and content validation mechanisms, as it allows attackers to inject malicious code that operates with the same permissions and privileges as the legitimate application itself.
Organizations using Progress Sitefinity 9.1 should implement immediate mitigations while planning for the upgrade to version 10.1 where this vulnerability has been addressed. The recommended approach includes implementing strict file validation that rejects html files containing javascript or other executable content, regardless of the upload context. Organizations should also consider implementing content security policies that limit the execution of inline scripts and restrict the ability of uploaded files to interact with the application's javascript environment. Additionally, administrators should review and restrict upload permissions to only those users who absolutely require this functionality, implementing principle of least privilege. The fix in version 10.1 addresses this vulnerability through enhanced file validation and improved content sanitization processes that prevent malicious code from being executed during the upload process. Organizations should also implement monitoring for suspicious file upload activities and consider deploying web application firewalls that can detect and block attempts to upload malicious content. The vulnerability demonstrates the importance of proper input validation and the dangers of trusting user-supplied content without adequate sanitization, particularly in web applications that serve dynamic content through user-uploaded files.