CVE-2013-1906 in Rules
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Rules module 7.x-2.x before 7.x-2.3 for Drupal allows remote authenticated users with the "administer rules" permission to inject arbitrary web script or HTML via a rule tag.
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Analysis
by VulDB Data Team • 02/27/2019
The vulnerability identified as CVE-2013-1906 represents a critical cross-site scripting flaw within the Rules module for Drupal version 7.x-2.x prior to 7.x-2.3. This security weakness specifically targets authenticated users who possess the "administer rules" permission, creating a significant risk for web applications that rely on Drupal's rule-based automation system. The vulnerability resides in how the module processes rule tags, allowing malicious actors to inject arbitrary web script or HTML content that can execute in the context of other users' browsers. The affected system architecture demonstrates a failure in proper input sanitization and output encoding mechanisms within the module's rule processing pipeline.
The technical implementation of this vulnerability stems from insufficient validation of user-supplied data within rule tags, which are used to define automated actions and conditions in Drupal's workflow system. When administrators create or modify rules through the web interface, the module fails to adequately sanitize the input before storing or rendering it in web pages. This oversight creates a persistent XSS vector where an attacker with administrative privileges can craft malicious rule configurations that, when executed or viewed by other users, will trigger script execution in their browsers. The vulnerability operates under CWE-79 which categorizes cross-site scripting as a weakness where applications fail to properly encode output, and aligns with ATT&CK technique T1059.001 for command and scripting interpreter execution through web-based interfaces.
The operational impact of this vulnerability extends beyond simple script injection, as it enables attackers to potentially escalate privileges, steal session cookies, perform unauthorized actions on behalf of other users, or redirect victims to malicious websites. Remote authenticated users with administrative access can leverage this flaw to compromise the entire Drupal installation, particularly when the rules module is used to automate sensitive operations or when administrators regularly execute or view rule configurations. The attack surface becomes particularly dangerous in environments where multiple administrators interact with the same rule-based systems, as a single compromised administrator account can lead to widespread exploitation across the application's user base. Organizations using vulnerable versions of the Rules module face potential data breaches, unauthorized access to sensitive systems, and complete compromise of their web application security posture.
Mitigation strategies for CVE-2013-1906 require immediate patching of the affected Drupal Rules module to version 7.x-2.3 or later, which includes proper input sanitization and output encoding measures. System administrators should implement strict access controls and privilege separation to minimize the attack surface, ensuring that only trusted personnel have "administer rules" permissions. Additional protective measures include monitoring rule creation activities, implementing web application firewalls to detect malicious script patterns, and conducting regular security audits of rule configurations. Organizations should also consider implementing content security policies to prevent execution of unauthorized scripts, while maintaining comprehensive logging of administrative activities to detect potential exploitation attempts. The remediation process must include thorough testing of updated modules to ensure compatibility with existing rule configurations and prevent service disruption during the security update process.