CVE-2017-9140 in Reporting for ASP.NET WebForms Report Viewer Control
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Telerik Reporting for ASP.NET WebForms Report Viewer control before R1 2017 SP2 (11.0.17.406) allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.
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Analysis
by VulDB Data Team • 10/01/2020
The vulnerability identified as CVE-2017-9140 represents a critical cross-site scripting flaw within the Telerik Reporting for ASP.NET WebForms Report Viewer control, specifically affecting versions prior to R1 2017 SP2. This vulnerability exposes web applications that utilize the Telerik reporting components to potential exploitation by remote attackers who can inject malicious web scripts or HTML content into the application interface. The flaw manifests through unspecified vectors within the report viewer component, making it particularly challenging to predict and defend against. The vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is classified as a fundamental web application security weakness that allows attackers to inject client-side scripts into web pages viewed by other users. The affected Telerik Reporting control is commonly used in enterprise environments for generating dynamic reports and dashboards, making it a prime target for attackers seeking to compromise web applications that rely on these reporting functionalities.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding within the Telerik Report Viewer control's handling of user-supplied data. When the control processes report parameters or data sources containing malicious script content, it fails to properly sanitize or escape the input before rendering it within the web page context. This allows attackers to inject JavaScript code or HTML elements that execute in the context of other users' browsers who view the affected reports. The unspecified vectors suggest that the vulnerability could be triggered through multiple pathways including report parameters, data binding operations, or even report design elements that are processed by the viewer control. Attackers can leverage this weakness to perform session hijacking, deface web applications, steal sensitive user information, or redirect victims to malicious websites. The vulnerability particularly impacts applications that dynamically generate reports based on user input or external data sources, where the report viewer component processes data without proper sanitization mechanisms.
The operational impact of CVE-2017-9140 extends beyond simple script injection, as it creates a persistent security risk that can be exploited for more sophisticated attacks within the targeted web applications. Organizations utilizing affected versions of the Telerik Reporting control face potential data breaches, unauthorized access to sensitive information, and compromise of user sessions. The vulnerability can be exploited to execute arbitrary code within the victim's browser context, potentially leading to complete compromise of user sessions through session theft or credential harvesting. Security professionals should note that this vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, which is part of the broader category of techniques used for executing malicious code in web environments. The attack surface is particularly concerning in enterprise environments where the report viewer component may be exposed to untrusted user inputs or where reports are generated from external data sources that could contain malicious content. Organizations running affected systems may experience reputational damage, regulatory compliance violations, and potential financial losses due to the exploitation of this vulnerability.
Organizations should immediately upgrade to Telerik Reporting R1 2017 SP2 or later versions to remediate this vulnerability, as the vendor has addressed the issue through proper input validation and output encoding mechanisms. Security teams should implement additional defensive measures including web application firewalls that can detect and block XSS payloads, regular security scanning of applications using the affected components, and comprehensive input validation policies. The remediation process should involve thorough testing of the updated reporting components to ensure that no regressions have occurred in report functionality while maintaining proper security hardening. Organizations should also conduct security awareness training for developers who work with the Telerik Reporting controls to prevent similar vulnerabilities in custom report implementations. Additionally, implementing Content Security Policy headers can provide an additional layer of protection against XSS attacks by restricting the sources from which scripts can be loaded and executed within the application context. The vulnerability serves as a reminder of the importance of keeping third-party components updated and implementing robust security practices in web application development processes, particularly when dealing with user-supplied data that is rendered within web interfaces.