CVE-2013-0206 in Live CSS
Summary
by MITRE
Unrestricted file upload vulnerability in the Live CSS module 6.x-2.x before 6.x-2.1 and 7.x-2.x before 7.x-2.7 for Drupal allows remote authenticated users with the "administer CSS" permissions to execute arbitrary code by uploading a file with an executable extension, then accessing it via a direct request to the file in an unspecified directory.
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Analysis
by VulDB Data Team • 02/09/2018
The CVE-2013-0206 vulnerability represents a critical unrestricted file upload flaw within the Live CSS module for Drupal platforms, affecting versions 6.x-2.x prior to 6.x-2.1 and 7.x-2.x prior to 7.x-2.7. This vulnerability specifically targets authenticated users who possess the "administer CSS" permission, creating a significant attack vector that can be exploited to achieve arbitrary code execution. The flaw resides in the module's inadequate validation of uploaded files, allowing malicious actors to bypass security controls and introduce potentially harmful content into the web application's file system.
The technical exploitation of this vulnerability involves a two-phase attack approach where an authenticated user with appropriate permissions uploads a file containing executable code with an extension that would typically be allowed in CSS contexts. The vulnerability stems from insufficient input validation and sanitization mechanisms within the Live CSS module, which fails to properly verify file types and extensions before storing uploaded content. This weakness aligns with CWE-434, which categorizes unrestricted file upload as a critical security flaw that can lead to arbitrary code execution. The vulnerability's impact is amplified by the fact that the uploaded files are stored in an unspecified directory, making them accessible via direct HTTP requests to the file paths.
The operational impact of CVE-2013-0206 extends beyond simple code execution to encompass full system compromise capabilities. Once an attacker successfully uploads a malicious file, they can execute arbitrary commands on the affected server, potentially leading to complete system takeover. This vulnerability can be leveraged for various malicious activities including data exfiltration, establishing persistent backdoors, or using the compromised system as a launch point for further attacks within the network. The attack requires only a user with minimal permissions, making it particularly dangerous as it can be exploited by insiders or through compromised accounts. From an ATT&CK framework perspective, this vulnerability maps to T1059 (Command and Scripting Interpreter) and T1078 (Valid Accounts) as it enables command execution and leverages legitimate user permissions.
Mitigation strategies for CVE-2013-0206 should prioritize immediate patching of affected Drupal installations to versions 6.x-2.1 or 7.x-2.7 respectively, which contain the necessary security fixes. Organizations should also implement additional defensive measures including restricting file upload capabilities to only essential file types, implementing strict file extension validation, and ensuring proper file permissions and directory access controls. Network-level protections such as web application firewalls can help detect and block suspicious file upload attempts. The vulnerability underscores the importance of principle of least privilege, where users should only be granted the minimum permissions necessary for their roles. Security teams should also conduct regular vulnerability assessments and implement proper monitoring for unauthorized file uploads. This incident highlights the critical need for robust input validation and secure coding practices, particularly in modules that handle user-provided content, as the vulnerability demonstrates how seemingly benign functionality can become a gateway for complete system compromise when proper security controls are absent.