CVE-2011-5148 in Mod Simplefileupload
Summary
by MITRE
Multiple incomplete blacklist vulnerabilities in the Simple File Upload (mod_simplefileuploadv1.3) module before 1.3.5 for Joomla! allow remote attackers to execute arbitrary code by uploading a file with a (1) php5, (2) php6, or (3) double (e.g. .php.jpg) extension, then accessing it via a direct request to the file in images/, as exploited in the wild in January 2012.
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Analysis
by VulDB Data Team • 12/23/2024
The vulnerability CVE-2011-5148 represents a critical security flaw in the Simple File Upload module for Joomla! versions prior to 1.3.5, exposing systems to remote code execution through improper file validation mechanisms. This issue stems from incomplete blacklist implementations that fail to properly restrict file extensions, creating pathways for attackers to bypass security controls and upload malicious payloads. The vulnerability specifically targets the module's inability to effectively block certain file extensions including php5, php6, and double extensions such as .php.jpg, which can evade detection by traditional security measures.
The technical exploitation of this vulnerability relies on the module's weak validation logic that does not adequately filter file extensions or content types during upload processes. Attackers can leverage this flaw by uploading a malicious PHP file with extensions that are not properly blacklisted, such as php5 or php6, or by using double extensions that appear benign but contain executable code. When these files are uploaded to the images/ directory and subsequently accessed through direct requests, they execute arbitrary code on the target server. This represents a classic case of insecure file upload vulnerability where the application fails to properly validate file content and extensions, allowing malicious files to be executed as web scripts.
From an operational impact perspective, this vulnerability enables attackers to gain full control over affected Joomla! installations, potentially leading to complete system compromise, data theft, or use as a foothold for further attacks within network infrastructure. The exploitation occurred in the wild during January 2012, demonstrating real-world threat actor interest in leveraging this weakness. Organizations running vulnerable versions of the Simple File Upload module faced significant risks including unauthorized access to sensitive data, website defacement, and potential use as command and control servers for broader attack campaigns. The vulnerability aligns with CWE-434, which describes "Unrestricted Upload of File with Dangerous Type," and represents a critical failure in input validation and file handling security controls.
The attack vector for this vulnerability follows established patterns found in the MITRE ATT&CK framework, specifically utilizing techniques related to T1190 - Exploit Public-Facing Application and T1059 - Command and Scripting Interpreter. The exploitation process demonstrates how attackers can leverage web application vulnerabilities to execute arbitrary code, potentially leading to privilege escalation and lateral movement within compromised environments. Organizations should implement comprehensive mitigations including proper file extension validation, content type checking, and removal of vulnerable modules from production environments. The vulnerability highlights the importance of proper input validation and the dangers of relying solely on blacklist-based security controls, which can be easily circumvented by attackers. Additionally, regular security audits and timely patch management are essential to prevent exploitation of such vulnerabilities in web applications.