CVE-2008-2574 in FlashBlog
Summary
by MITRE
Unrestricted file upload vulnerability in admin/Editor/imgupload.php in FlashBlog 0.31 beta allows remote attackers to execute arbitrary code by uploading a .php file, then accessing it via a direct request to the file in tus_imagenes/.
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Analysis
by VulDB Data Team • 10/27/2024
The vulnerability described in CVE-2008-2574 represents a critical unrestricted file upload flaw within the FlashBlog 0.31 beta content management system. This issue resides in the administrative file upload functionality located at admin/Editor/imgupload.php, which fails to properly validate or sanitize file uploads. The vulnerability enables remote attackers to bypass security restrictions and upload malicious PHP files directly to the server. Once uploaded, these files can be executed by the web server, providing attackers with arbitrary code execution capabilities. The specific directory path tus_imagenes/ serves as the target location where uploaded files are stored, making it possible for attackers to directly access and execute their malicious payloads through simple HTTP requests.
This vulnerability directly maps to CWE-434, which defines unrestricted file upload as a weakness where applications allow users to upload files without proper validation of file type, content, or destination. The flaw constitutes a severe security oversight that violates fundamental web application security principles. Attackers can exploit this vulnerability by crafting malicious PHP files with web shell functionality or other malicious code, then uploading these files through the vulnerable upload interface. The lack of proper file type validation, content inspection, or file extension filtering creates an exploitable pathway for attackers to gain persistent access to the underlying server infrastructure.
The operational impact of this vulnerability is substantial and multifaceted. Remote code execution capabilities allow attackers to perform various malicious activities including data exfiltration, system reconnaissance, privilege escalation, and establishment of persistent backdoors. The vulnerability affects the entire web application stack since uploaded files are immediately executable, eliminating the need for additional exploitation techniques. Organizations running FlashBlog 0.31 beta systems face significant risk of complete system compromise, data breaches, and potential use as a launching point for further attacks within their network infrastructure. The vulnerability also impacts the integrity and availability of the web application, as attackers can modify or delete system files, potentially causing service disruption.
Mitigation strategies for this vulnerability should focus on implementing comprehensive file upload validation controls. Organizations must enforce strict file type validation by checking MIME types, file extensions, and file content signatures rather than relying solely on client-side validation. The upload directory should be configured with restricted permissions and should not be executable by the web server. Implementing a whitelist approach for allowed file types, such as only permitting image formats like jpg, png, and gif, while rejecting PHP, ASP, or other executable file types, provides effective protection. Additionally, uploaded files should be stored in a non-executable directory and renamed using a random or unique identifier to prevent direct access. This vulnerability aligns with ATT&CK technique T1505.003 for server-side web shell execution and T1078 for valid accounts usage, emphasizing the need for proper access controls and monitoring of file upload activities. The fix requires immediate patching of the vulnerable FlashBlog version or complete removal of the insecure upload functionality until proper security controls are implemented.