CVE-2009-3656 in Shared Sign-On
Summary
by MITRE
Cross-site request forgery (CSRF) vulnerability in Shared Sign-On 5.x and 6.x, a module for Drupal, allows remote attackers to hijack the authentication of arbitrary users via unknown vectors.
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Analysis
by VulDB Data Team • 12/23/2017
The CVE-2009-3656 vulnerability represents a critical cross-site request forgery flaw within the Shared Sign-On module version 5.x and 6.x for the Drupal content management system. This vulnerability resides in the authentication handling mechanisms of the module, which is designed to facilitate single sign-on functionality across multiple Drupal sites. The flaw enables remote attackers to manipulate authenticated sessions by exploiting the absence of proper request validation controls. The vulnerability's impact extends beyond simple session hijacking as it allows attackers to perform actions on behalf of authenticated users without their knowledge or consent.
The technical implementation of this CSRF vulnerability stems from insufficient validation of the origin and authenticity of HTTP requests within the Shared Sign-On module. The module fails to properly verify that requests originate from legitimate sources within the same domain, allowing malicious actors to craft specially crafted requests that appear to come from authenticated users. This weakness creates an environment where attackers can leverage the trust relationship between the user's browser and the Drupal application to execute unauthorized operations. The vulnerability operates at the application layer and specifically targets the session management and authentication token validation processes that are fundamental to web application security.
From an operational perspective, this vulnerability poses significant risks to organizations relying on Drupal with the Shared Sign-On module. Attackers can exploit this flaw to perform privileged actions such as creating new user accounts, modifying existing user permissions, accessing sensitive data, or executing administrative functions within the Drupal environment. The remote nature of the attack means that threat actors do not require physical access to the system or knowledge of valid credentials to exploit the vulnerability. This makes the attack surface particularly dangerous as it can be executed from anywhere on the internet, potentially leading to complete system compromise. The vulnerability's presence in widely used Drupal versions amplifies its potential impact across numerous websites and organizations.
Security professionals should address this vulnerability through immediate patching of the Shared Sign-On module to version 7.x or later, which contains the necessary CSRF protection mechanisms. Organizations should also implement additional defensive measures such as ensuring proper CSRF token validation throughout the application, implementing Content Security Policy headers, and conducting regular security assessments of third-party modules. The vulnerability aligns with CWE-352, which specifically addresses Cross-Site Request Forgery weaknesses in web applications. From an attacker perspective, this vulnerability maps to ATT&CK technique T1566.002 which involves the exploitation of web application vulnerabilities for initial access and privilege escalation. Organizations should also consider implementing web application firewalls and monitoring for suspicious authentication-related activities to detect potential exploitation attempts. The remediation process should include comprehensive testing to ensure that the patch does not introduce compatibility issues with existing functionality while maintaining the integrity of the authentication system.