CVE-2017-6930 in Drupal
Summary
by MITRE
In Drupal versions 8.4.x versions before 8.4.5 when using node access controls with a multilingual site, Drupal marks the untranslated version of a node as the default fallback for access queries. This fallback is used for languages that do not yet have a translated version of the created node. This can result in an access bypass vulnerability. This issue is mitigated by the fact that it only applies to sites that a) use the Content Translation module; and b) use a node access module such as Domain Access which implement hook_node_access_records().
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Analysis
by VulDB Data Team • 02/10/2023
The vulnerability described in CVE-2017-6930 represents a critical access control flaw within the Drupal content management system that specifically impacts multilingual configurations. This issue affects Drupal 8.4.x versions prior to 8.4.5 and stems from how the system handles node access queries when content translation is enabled. The flaw manifests when Drupal attempts to determine access permissions for nodes that have not yet been translated into a specific language, creating a potential security bypass that could allow unauthorized users to access content they should not be permitted to view.
The technical root cause of this vulnerability lies in Drupal's handling of untranslated node versions within multilingual environments. When a node exists in one language but has not yet been translated into another language, the system defaults to using the untranslated version as the fallback for access control queries. This fallback mechanism, while intended to provide a default state for content access, creates a security gap that can be exploited by attackers who understand the system's behavior. The vulnerability specifically occurs when sites utilize both the Content Translation module and node access modules such as Domain Access that implement the hook_node_access_records() function, which is a key component in how Drupal manages access control for content.
The operational impact of this vulnerability is significant for organizations running multilingual Drupal sites with content translation enabled. Attackers could potentially bypass access controls to view content that should only be accessible to specific user roles or groups, particularly when dealing with content that has not yet been translated into certain languages. This access bypass could lead to unauthorized exposure of sensitive information, private content, or restricted materials that should remain hidden from general users or users without proper permissions. The vulnerability's scope is limited to specific configurations, but for affected sites, the implications are severe enough to warrant immediate attention and remediation.
The mitigation strategy for this vulnerability involves upgrading to Drupal 8.4.5 or later versions where the issue has been patched. Organizations should also carefully evaluate their site configurations to ensure they are not running affected versions of the software. Security teams should implement monitoring for any unauthorized access attempts that might indicate exploitation of this vulnerability. Additionally, organizations using the Content Translation module should review their access control configurations and consider implementing additional security measures such as more restrictive node access rules or custom access control modules. This vulnerability aligns with CWE-284, which addresses improper access control, and represents a specific case where weak fallback mechanisms in multilingual content management systems create exploitable security gaps. The ATT&CK framework categorizes this as a privilege escalation technique through access control bypass, where attackers exploit system-level weaknesses to gain unauthorized access to protected resources.