CVE-2008-6178 in PHPList
Summary
by MITRE
Unrestricted file upload vulnerability in editor/filemanager/browser/default/connectors/php/connector.php in FCKeditor 2.2, as used in Falt4 CMS, Nuke ET, and other products, allows remote attackers to execute arbitrary code by creating a file with PHP sequences preceded by a ZIP header, uploading this file via a FileUpload action with the application/zip content type, and then accessing this file via a direct request to the file in UserFiles/File/, probably a related issue to CVE-2005-4094. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 11/24/2024
The vulnerability described in CVE-2008-6178 represents a critical unrestricted file upload flaw in FCKeditor 2.2, a widely deployed web-based rich text editor component. This vulnerability affects multiple content management systems including Falt4 CMS and Nuke ET, making it particularly dangerous due to the widespread adoption of these platforms. The flaw exists within the file management connector implementation at editor/filemanager/browser/default/connectors/php/connector.php, where the application fails to properly validate file types during the upload process. Attackers can exploit this weakness by crafting malicious files that contain PHP code sequences preceded by a legitimate ZIP file header, effectively bypassing standard file type checks that are typically designed to prevent execution of script files.
The technical exploitation mechanism leverages the specific way FCKeditor handles file uploads with application/zip content type, allowing attackers to upload files that appear to be compressed archives but actually contain executable PHP code. When the malicious file is uploaded to the UserFiles/File/ directory, the attacker can subsequently access it directly through a web request, enabling arbitrary code execution on the vulnerable server. This type of vulnerability falls under CWE-434, which specifically addresses "Unrestricted Upload of File with Dangerous Type," and represents a classic example of how improper input validation can lead to remote code execution. The vulnerability is particularly concerning because it operates at the intersection of file handling and content type validation, where the ZIP header serves as a deceptive mechanism to mask malicious payloads within what appears to be a benign file format.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as it provides attackers with complete control over the affected web server. Once successfully exploited, adversaries can execute arbitrary commands, upload additional malicious tools, establish backdoors, or use the compromised server as a launching point for further attacks within the network. The vulnerability's relationship to CVE-2005-4094 indicates that it represents a persistent pattern of flawed file upload validation that has affected multiple versions of similar components, highlighting the need for comprehensive security reviews of file handling mechanisms. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1059.007, which involves executing malicious code through web shells or command injection, and demonstrates how seemingly minor validation flaws can result in complete system compromise.
Organizations affected by this vulnerability should implement immediate mitigations including strict file type validation, removal of executable file extensions from upload directories, and implementation of proper content type checking mechanisms. The recommended approach involves configuring web servers to deny execution of PHP files in upload directories, implementing whitelisting of allowed file extensions, and ensuring that all file uploads undergo comprehensive validation before being stored on the server. Additionally, security measures should include regular vulnerability assessments, monitoring of upload directories for suspicious files, and implementing proper access controls that prevent unauthorized file access. This vulnerability serves as a critical reminder of the importance of proper input validation and the potential consequences of inadequate security controls in web applications, particularly those handling user-supplied content. The incident underscores the necessity of following security best practices such as those outlined in OWASP Top Ten and other industry standards that emphasize the importance of validating file uploads and implementing defense-in-depth strategies to protect against similar vulnerabilities.