CVE-2009-0818 in Taxonomy Theme module
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the taxonomy_theme_admin_table_builder function (taxonomy_theme_admin.inc) in Taxonomy Theme module before 5.x-1.2, a module for Drupal, allows remote authenticated users with the "administer taxonomy" permission, or the ability to create pages when tagging is enabled, to inject arbitrary web script or HTML via the Vocabulary name (name parameter) to index.php. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 11/26/2017
The CVE-2009-0818 vulnerability represents a critical cross-site scripting flaw within the Drupal Taxonomy Theme module, specifically in the taxonomy_theme_admin_table_builder function located in taxonomy_theme_admin.inc. This vulnerability affects Drupal versions prior to 5.x-1.2 and demonstrates a classic input validation weakness that can be exploited by authenticated attackers with specific permissions. The flaw occurs when the system fails to properly sanitize user input during the processing of vocabulary names, creating an avenue for malicious script injection that can persist across user sessions and potentially compromise the entire Drupal installation.
The technical exploitation of this vulnerability requires an attacker to possess either the "administer taxonomy" permission or the capability to create pages with tagging functionality enabled. When a malicious user submits a crafted vocabulary name containing embedded script tags or HTML content through the name parameter in index.php, the system processes this input without adequate sanitization. The vulnerability stems from the module's failure to implement proper output encoding or input validation mechanisms, allowing the malicious payload to be stored in the system and subsequently executed whenever the affected page is rendered. This type of vulnerability maps directly to CWE-79 which categorizes cross-site scripting as a critical weakness in web applications, specifically addressing the improper handling of untrusted data in web applications.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the ability to perform session hijacking, steal sensitive administrative credentials, or manipulate the taxonomy interface to redirect users to malicious websites. An attacker with administrative privileges could potentially use this vulnerability to modify or delete taxonomy terms, alter content relationships, or even escalate their privileges within the Drupal system. The persistence of the vulnerability means that once exploited, the malicious scripts remain active until manually removed by system administrators, creating a long-term security risk that can affect all users interacting with the affected taxonomy interface. This aligns with ATT&CK technique T1059.007 for command and scripting interpreter, where adversaries use web-based scripting to maintain persistence and execute malicious payloads.
Mitigation strategies for this vulnerability involve immediate patching to version 5.x-1.2 or later of the Taxonomy Theme module, which includes proper input sanitization and output encoding mechanisms. Organizations should also implement additional security measures such as input validation at multiple layers, output encoding for all dynamic content, and regular security audits of contributed modules. The principle of least privilege should be enforced by limiting the "administer taxonomy" permission to only essential administrators, while also monitoring user activities that involve taxonomy management. Additionally, implementing Content Security Policy headers can provide an additional layer of protection against script injection attacks, though this does not replace proper input validation. Regular security assessments of Drupal installations, including vulnerability scanning and code review of contributed modules, remain essential practices for maintaining system integrity and preventing exploitation of similar weaknesses in the taxonomy management system.