CVE-2012-5653 in Drupal
Summary
by MITRE
The file upload feature in Drupal 6.x before 6.27 and 7.x before 7.18 allows remote authenticated users to bypass the protection mechanism and execute arbitrary PHP code via a null byte in a file name.
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Analysis
by VulDB Data Team • 12/21/2021
The vulnerability identified as CVE-2012-5653 represents a critical security flaw in the Drupal content management system affecting versions 6.x prior to 6.27 and 7.x prior to 7.18. This issue resides within the file upload functionality and demonstrates how inadequate input validation can lead to severe remote code execution capabilities. The vulnerability specifically exploits a weakness in the file name sanitization process, allowing authenticated attackers to circumvent security protections through the strategic insertion of null bytes in file names.
The technical implementation of this vulnerability stems from improper handling of null byte characters within file names during the upload process. When a user uploads a file containing a null byte in its name, the system fails to properly sanitize this input, creating a pathway for malicious code execution. The flaw operates at the intersection of input validation and file processing, where the null byte terminates string processing in certain contexts, effectively bypassing the intended file type restrictions and security checks. This behavior aligns with CWE-174, which addresses insufficient sanitization of null bytes in input strings, and demonstrates how seemingly minor input validation gaps can result in catastrophic security implications.
The operational impact of CVE-2012-5653 extends far beyond simple privilege escalation, as it enables authenticated attackers to execute arbitrary PHP code on affected systems. This capability fundamentally compromises the integrity and confidentiality of web applications, potentially allowing attackers to gain full control over the affected Drupal installations. The vulnerability is particularly dangerous because it requires only authenticated access, meaning that any user with legitimate credentials can exploit the flaw. This characteristic places the vulnerability in the ATT&CK framework under the T1078 technique for Valid Accounts, as attackers can leverage existing user credentials to achieve code execution without requiring additional exploitation methods. The attack vector specifically targets the T1190 technique for Exploit Public-Facing Application, where the vulnerability exists in a publicly accessible feature of the web application.
Organizations running affected Drupal versions face significant risks including data breaches, system compromise, and potential lateral movement within network environments. The vulnerability allows attackers to upload malicious files that can execute PHP code, potentially leading to complete system takeover. Security professionals should consider this vulnerability alongside other file upload vulnerabilities such as those classified under CWE-434, which addresses insecure file upload handling. The attack surface expands when considering that Drupal installations often contain sensitive data and may serve as entry points for broader network infiltration attempts. Remediation efforts must include immediate patching of affected systems, implementation of additional input validation measures, and comprehensive monitoring for signs of exploitation attempts.
The mitigation strategy for CVE-2012-5653 centers on applying the official security patches released by the Drupal project, specifically version 6.27 for Drupal 6.x and version 7.18 for Drupal 7.x. Organizations should also implement additional defensive measures including stricter file upload restrictions, enhanced input validation at multiple layers, and regular security audits of file handling processes. Network-based intrusion detection systems should be configured to monitor for suspicious file upload patterns, while application firewalls can provide additional protection against malformed file name inputs. The vulnerability serves as a reminder of the importance of proper input validation and the potential consequences of inadequate sanitization of user-supplied data, particularly in web applications that handle file uploads. Security teams should also consider implementing automated patch management processes to ensure timely deployment of security updates and prevent similar vulnerabilities from remaining unaddressed in production environments.