CVE-2011-1329 in WalRack
Summary
by MITRE
WalRack 1.x before 1.1.9 and 2.x before 2.0.7 does not properly restrict file uploads, which allows remote attackers to execute arbitrary PHP code via vectors involving a double extension, as demonstrated by a .php.zzz file.
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Analysis
by VulDB Data Team • 03/23/2015
The vulnerability identified as CVE-2011-1329 affects WalRack content management systems across versions 1.x before 1.1.9 and 2.x before 2.0.7, representing a critical security flaw in file upload validation mechanisms. This issue stems from insufficient input sanitization and improper file extension handling within the application's upload functionality, creating a pathway for remote code execution attacks. The vulnerability specifically manifests when attackers exploit the system's failure to properly validate file extensions, particularly in cases involving double extensions that bypass conventional security checks.
The technical exploitation of this vulnerability relies on a sophisticated attack vector involving double file extensions where malicious PHP code is embedded within files that appear benign to the upload validation system. When an attacker uploads a file with a double extension such as .php.zzz, the system may incorrectly process this file by only examining the final extension, thereby allowing the PHP code to execute on the server. This technique demonstrates a fundamental flaw in the application's file validation logic, which fails to properly parse and validate the complete file name structure. The vulnerability operates at the intersection of improper input validation and insecure file handling practices, creating a condition where the system's trust in file extensions is manipulated to execute malicious code.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with complete control over the affected server environment. Remote attackers can leverage this vulnerability to upload backdoor scripts, modify existing files, escalate privileges, or establish persistent access to the compromised system. The implications are particularly severe in web hosting environments where multiple users share the same infrastructure, as successful exploitation could lead to complete system compromise and data exfiltration. This vulnerability directly aligns with CWE-434, which addresses insecure file upload vulnerabilities, and represents a classic example of how inadequate input validation can lead to remote code execution. The attack vector is particularly dangerous because it can be executed without requiring authentication, making it accessible to any remote user with access to the upload functionality.
Mitigation strategies for this vulnerability must address both the immediate security gap and broader architectural weaknesses in the application's file handling mechanisms. Organizations should implement strict file extension validation that examines the complete file name structure rather than relying on simple extension checks, and should employ content type verification alongside traditional extension validation. The recommended approach includes implementing a whitelist of allowed file extensions, enforcing proper file name sanitization, and implementing server-side validation that cannot be bypassed through client-side manipulation. Additionally, the system should separate uploaded files from executable code and implement proper access controls to prevent direct execution of uploaded files. This vulnerability demonstrates the importance of following secure coding practices as outlined in the OWASP Top Ten and aligns with ATT&CK technique T1190 for exploiting vulnerabilities in web applications. Organizations must also consider implementing web application firewalls and intrusion detection systems to monitor for suspicious upload activities and prevent exploitation attempts.