CVE-2016-3188 in Prepopulate Module
Summary
by MITRE
The _prepopulate_request_walk function in the Prepopulate module 7.x-2.x before 7.x-2.1 for Drupal allows remote attackers to modify the (1) actions, (2) container, (3) token, (4) password, (5) password_confirm, (6) text_format, or (7) markup field type, and consequently have unspecified impact, via unspecified vectors.
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Analysis
by VulDB Data Team • 07/13/2022
The vulnerability identified as CVE-2016-3188 affects the Prepopulate module version 7.x-2.x before 7.x-2.1 in Drupal content management systems, representing a significant security flaw that enables remote attackers to manipulate critical form field types through the _prepopulate_request_walk function. This vulnerability falls under the category of insecure direct object reference and input validation issues, with potential implications that align with CWE-284 access control weaknesses and CWE-94 code injection vulnerabilities. The Prepopulate module is designed to prefill form fields with data from URL parameters, which is a common functionality for creating dynamic user experiences, but this particular implementation contains a critical flaw in its parameter handling mechanism.
The technical flaw manifests when the _prepopulate_request_walk function processes incoming HTTP requests without proper validation of the field types being modified. Attackers can exploit this by crafting malicious URLs that contain specially formatted parameters targeting the seven specific field types mentioned in the vulnerability description. These include actions, container, token, password, password_confirm, text_format, and markup field types, all of which can be manipulated to alter form behavior or content. The unspecified vectors suggest that the attack surface is broad and can potentially be exploited through various HTTP request methods, parameter injection techniques, or even through cross-site scripting scenarios that leverage the module's functionality.
The operational impact of this vulnerability is substantial as it provides attackers with the capability to perform unauthorized modifications to form submissions and potentially gain access to sensitive user data or system functionality. When attackers manipulate password and password_confirm fields, they could potentially bypass authentication mechanisms or create unauthorized account access. The ability to modify text_format and markup fields creates risks for cross-site scripting attacks where malicious HTML or JavaScript code could be injected into the system. The container and token field modifications could lead to privilege escalation or denial of service conditions, while actions field manipulation could alter the intended behavior of form processing workflows. This vulnerability essentially allows for arbitrary form field modification, which could result in data corruption, unauthorized access, or complete system compromise depending on the specific implementation and access controls in place.
Mitigation strategies for CVE-2016-3188 should prioritize immediate patching of the Prepopulate module to version 7.x-2.1 or later, as this represents the most direct and effective solution to address the vulnerability. Organizations should also implement network-level controls such as web application firewalls that can detect and block suspicious parameter patterns targeting the vulnerable field types. Input validation should be strengthened at multiple levels, including validating field type parameters against a whitelist of acceptable values and implementing proper sanitization of all user-supplied data. Security teams should conduct comprehensive code reviews of all custom modules that interact with form processing functionality and ensure that proper access controls are implemented for form field modifications. Additionally, monitoring and logging of form submission activities should be enhanced to detect anomalous patterns that might indicate exploitation attempts, and regular security assessments should be performed to identify similar vulnerabilities in other modules or custom code implementations. The vulnerability's classification under ATT&CK technique T1213 (Data from Information Repositories) and T1078 (Valid Accounts) highlights the potential for credential theft and unauthorized access through this exploit path, emphasizing the need for layered defensive measures.