CVE-2012-2725 in 6.x-1.0
Summary
by MITRE
classes/Filter/WhitelistedExternalFilter.php in the Authoring HTML module 6.x-1.x before 6.x-1.1 for Drupal does not properly validate sources with the host white list, which allows remote authenticated users to bypass intended access restrictions and conduct cross-site scripting (XSS) attacks.
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Analysis
by VulDB Data Team • 01/17/2018
The vulnerability identified as CVE-2012-2725 resides within the Authoring HTML module version 6.x-1.x of the Drupal content management system prior to the 6.x-1.1 release. This flaw specifically affects the WhitelistedExternalFilter.php file which is responsible for validating external sources in HTML content. The issue manifests when the module fails to properly validate sources against a configured host whitelist, creating a security gap that can be exploited by authenticated users. The vulnerability represents a critical weakness in Drupal's input validation mechanisms, particularly concerning external resource handling within HTML content filtering.
The technical flaw stems from insufficient validation logic in the external filter implementation where the module does not adequately verify that external sources originate from hosts explicitly listed in the whitelist configuration. This improper validation allows authenticated users to craft malicious HTML content that bypasses the intended access restrictions. The vulnerability specifically enables cross-site scripting attacks by permitting the inclusion of external resources that could contain malicious scripts, effectively undermining the security controls designed to prevent unauthorized content execution. The flaw operates at the input sanitization layer, where external references should be strictly controlled but are instead permitted through inadequate validation checks.
The operational impact of this vulnerability is significant for Drupal installations using the affected module, as it allows authenticated users to perform XSS attacks against other users of the system. This creates a persistent threat vector where compromised users can execute malicious scripts in the context of other users' browsers, potentially leading to session hijacking, data theft, or further system compromise. The vulnerability affects the integrity of the content management system by allowing unauthorized code execution within the HTML filtering context, undermining the security assumptions of the module's access control mechanisms. Attackers can leverage this weakness to target other users with malicious content that appears to originate from trusted external sources.
Mitigation strategies for CVE-2012-2725 involve immediate upgrading to the patched version 6.x-1.1 of the Authoring HTML module, which addresses the validation logic flaw. Organizations should also implement additional defensive measures including stricter input validation policies, regular security audits of module configurations, and monitoring for unauthorized modifications to whitelist configurations. The vulnerability aligns with CWE-20 Improper Input Validation and can be categorized under ATT&CK technique T1059.008 Command and Scripting Interpreter: PowerShell, as it enables the execution of malicious scripts through compromised content filtering. System administrators should also consider implementing web application firewalls and content security policies to provide additional layers of protection against similar vulnerabilities in the future.