CVE-2009-0603 in Link module
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in index.php in the Link module 5.x-2.5 for Drupal 5.10 allows remote authenticated users, with "administer content types" privileges, to inject arbitrary web script or HTML via the description parameter (aka the Help field). NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 11/25/2017
The vulnerability described in CVE-2009-0603 represents a classic cross-site scripting flaw within the Drupal content management system's Link module version 5.x-2.5. This issue specifically affects Drupal version 5.10 and demonstrates how seemingly benign administrative functions can become attack vectors when proper input validation mechanisms are absent. The vulnerability exists in the index.php file of the Link module, where user-supplied data from the description parameter is not adequately sanitized before being rendered back to users. This particular flaw requires an attacker to possess administrative privileges, specifically the "administer content types" permission, which significantly reduces the attack surface but does not eliminate the risk entirely. The affected parameter corresponds to what is known as the Help field within the module's interface, making it accessible through standard administrative workflows that content creators and administrators routinely use.
The technical exploitation of this vulnerability occurs through the manipulation of the description parameter within the Link module's administrative interface. When an authenticated user with sufficient privileges submits malicious script code through this field, the system fails to properly escape or filter the input before storing it in the database. Subsequently, when other users access pages that display this stored content, the malicious script executes in their browsers within the context of the vulnerable website. This behavior constitutes a reflected cross-site scripting attack where the malicious payload is stored server-side and executed when legitimate users browse pages containing the compromised data. The vulnerability aligns with CWE-79 which specifically addresses Cross-site Scripting flaws in web applications, and the attack pattern follows the standard methodology described in the MITRE ATT&CK framework under the technique of Web Application Attack Vectors. The flaw essentially bypasses the application's security controls by leveraging the elevated privileges of the authenticated user to inject malicious content that will be executed by other users.
The operational impact of CVE-2009-0603 extends beyond simple script execution and can enable attackers to perform various malicious activities once they have achieved code execution in victim browsers. Attackers could potentially steal session cookies, redirect users to malicious websites, deface the website content, or even escalate their privileges further within the compromised Drupal installation. The vulnerability is particularly concerning because it requires only administrative access rather than full system compromise, making it more accessible to attackers who have gained some level of access to the administrative interface. The stored nature of the XSS payload means that the attack can persist for extended periods, potentially affecting numerous users over time. Organizations running affected Drupal installations could face significant reputational damage, data breaches, and potential regulatory compliance violations depending on the nature of the data being processed through the vulnerable module. The vulnerability also demonstrates the importance of input sanitization even within administrative interfaces where users are trusted, as these areas often receive less scrutiny from security testing.
Mitigation strategies for CVE-2009-0603 should focus on immediate patching of the affected Drupal installation and implementation of proper input validation mechanisms. The primary solution involves upgrading to a patched version of the Link module or Drupal core that properly sanitizes user input before storage and rendering. Organizations should also implement additional security controls such as input validation, output encoding, and content security policies to prevent similar vulnerabilities from occurring in other parts of the application. Regular security audits and code reviews should be conducted to identify potential injection points, particularly in modules that handle user-supplied content. The principle of least privilege should be enforced to limit administrative access to only those users who absolutely require it, reducing the potential impact of such vulnerabilities. Additionally, web application firewalls and intrusion detection systems can provide additional layers of protection by monitoring for suspicious patterns in user input. Organizations should also consider implementing automated security testing tools that can identify XSS vulnerabilities in their applications, as this particular flaw could have been detected through proper security scanning procedures. The vulnerability serves as a reminder that even authenticated users with elevated privileges can pose security risks if proper sanitization controls are not in place throughout the entire application stack.