CVE-2009-0781 in Tomcat
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in jsp/cal/cal2.jsp in the calendar application in the examples web application in Apache Tomcat 4.1.0 through 4.1.39, 5.5.0 through 5.5.27, and 6.0.0 through 6.0.18 allows remote attackers to inject arbitrary web script or HTML via the time parameter, related to "invalid HTML."
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Analysis
by VulDB Data Team • 08/30/2019
The vulnerability described in CVE-2009-0781 represents a classic cross-site scripting flaw within the Apache Tomcat examples web application, specifically in the calendar component's jsp/cal/cal2.jsp file. This issue affects multiple versions of the Tomcat server including the 4.1.x series up to 4.1.39, 5.5.x series up to 5.5.27, and 6.0.x series up to 6.0.18. The flaw manifests when the application fails to properly sanitize user input, particularly in the time parameter of the calendar functionality, allowing malicious actors to inject arbitrary web scripts or HTML code into the application's response. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is one of the most prevalent and dangerous web application security flaws identified by the Common Weakness Enumeration catalog.
The technical implementation of this vulnerability stems from improper input validation and output encoding within the calendar application's JSP component. When users provide input through the time parameter, the application processes this data without adequate sanitization measures, creating an injection point for malicious scripts. The vulnerability is particularly concerning because it allows attackers to execute arbitrary web scripts in the context of the victim's browser, potentially leading to session hijacking, credential theft, or redirection to malicious sites. The "invalid HTML" reference in the description indicates that the flaw specifically relates to how the application handles malformed or unexpected HTML content in the time parameter, suggesting that the input validation logic fails to properly escape or filter special characters that could be interpreted as HTML or script tags.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with a foothold for more sophisticated attacks within the web application environment. An attacker could exploit this vulnerability to steal session cookies, redirect users to phishing sites, or even execute malicious code that could compromise the entire web application or underlying server. The affected versions of Apache Tomcat were widely deployed across enterprise environments, making this vulnerability particularly dangerous as it could potentially affect numerous organizations running legacy applications. The vulnerability's presence in the examples web application, which is typically deployed for demonstration purposes but often remains accessible in production environments, compounds the risk as it provides attackers with an easily identifiable attack surface.
Organizations should implement multiple layers of mitigation strategies to address this vulnerability effectively. The primary remediation involves upgrading to patched versions of Apache Tomcat where the input validation has been properly implemented and the time parameter is adequately sanitized. Additionally, implementing proper output encoding techniques when rendering user-supplied data can prevent script execution even if input validation fails. Security headers such as Content Security Policy should be configured to limit script execution within the application context. The vulnerability aligns with ATT&CK technique T1059.007 for script injection and T1531 for credential theft, making it a significant concern for organizations following the MITRE ATT&CK framework for threat modeling. Regular input validation testing and web application firewalls should be deployed to detect and prevent exploitation attempts, while security awareness training for developers can help prevent similar issues in custom application code. Organizations should also consider implementing automated scanning tools that can identify similar XSS vulnerabilities in their web applications and ensure that all components within the Tomcat environment are properly patched and maintained.