CVE-2011-2087 in Struts
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in component handlers in the javatemplates (aka Java Templates) plugin in Apache Struts 2.x before 2.2.3 allow remote attackers to inject arbitrary web script or HTML via an arbitrary parameter value to a .action URI, related to improper handling of value attributes in (1) FileHandler.java, (2) HiddenHandler.java, (3) PasswordHandler.java, (4) RadioHandler.java, (5) ResetHandler.java, (6) SelectHandler.java, (7) SubmitHandler.java, and (8) TextFieldHandler.java.
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Analysis
by VulDB Data Team • 02/09/2019
The vulnerability described in CVE-2011-2087 represents a critical cross-site scripting flaw within the Apache Struts 2 framework's Java Templates plugin, specifically affecting versions prior to 2.2.3. This issue stems from inadequate input validation and sanitization mechanisms within the component handlers that process form elements and user-provided data. The vulnerability manifests when attackers can inject malicious scripts through parameter values submitted to .action URIs, creating a persistent security risk for applications that rely on the affected Struts versions.
The technical flaw resides in the improper handling of value attributes within eight distinct handler classes within the javatemplates component. These handlers include FileHandler.java, HiddenHandler.java, PasswordHandler.java, RadioHandler.java, ResetHandler.java, SelectHandler.java, SubmitHandler.java, and TextFieldHandler.java, each responsible for processing different HTML form elements. The vulnerability occurs because these handlers fail to properly escape or sanitize user input before rendering it into HTML output, allowing attackers to inject malicious JavaScript code or HTML content that executes in the context of other users' browsers.
The operational impact of this vulnerability is severe and far-reaching, as it enables remote code execution through browser-based attacks without requiring authentication or privileged access. Attackers can exploit these XSS vulnerabilities to steal session cookies, perform unauthorized actions on behalf of users, redirect victims to malicious sites, or deface web applications. The attack vector is particularly dangerous because it leverages the .action URI pattern commonly used in Struts applications, making it difficult to distinguish between legitimate and malicious requests. This vulnerability directly maps to CWE-79, which defines Cross-Site Scripting as a weakness that occurs when an application includes untrusted data in a new web page without proper validation or escaping.
The attack surface extends beyond simple script injection to include potential privilege escalation and data theft scenarios. When exploited, these vulnerabilities can allow attackers to access sensitive user information, manipulate application functionality, and potentially gain access to backend systems if applications lack proper input validation. The vulnerability affects web applications built on Apache Struts 2.x frameworks where user input is processed through the affected handler components, making it particularly dangerous for enterprise applications that rely heavily on Struts for web application development.
Mitigation strategies for CVE-2011-2087 include immediate upgrading to Apache Struts 2.2.3 or later versions where the vulnerability has been addressed through proper input sanitization and output escaping mechanisms. Organizations should also implement comprehensive input validation at multiple layers of their application architecture, including client-side and server-side validation, to prevent malicious input from reaching the vulnerable handlers. Additionally, implementing Content Security Policy headers, using proper output encoding techniques, and conducting regular security code reviews can help reduce the risk of exploitation. The vulnerability demonstrates the importance of secure coding practices and proper input validation, aligning with ATT&CK technique T1566 which covers the exploitation of web application vulnerabilities for initial access and privilege escalation purposes.