CVE-2007-4640 in Pakupaku CMS
Summary
by MITRE
Unrestricted file upload vulnerability in index.php in Pakupaku CMS 0.4 and earlier allows remote attackers to upload and execute arbitrary PHP files in uploads/ via an Uploads action.
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Analysis
by VulDB Data Team • 10/02/2024
The CVE-2007-4640 vulnerability represents a critical unrestricted file upload flaw in Pakupaku CMS version 0.4 and earlier, exposing web applications to remote code execution risks. This vulnerability resides in the index.php file and specifically affects the Uploads action functionality, creating a pathway for attackers to bypass security controls and deploy malicious payloads directly to the server's upload directory. The flaw fundamentally stems from inadequate input validation and sanitization mechanisms that fail to properly inspect or restrict file types during the upload process, allowing attackers to submit files with potentially dangerous extensions or content.
The technical exploitation of this vulnerability follows a well-established pattern within the cybersecurity landscape, where attackers leverage weak server-side validation to upload malicious files that can execute arbitrary code on the target system. This particular flaw aligns with CWE-434, which specifically addresses the insecure upload of executable files, and represents a classic example of how insufficient access control and file validation can lead to complete system compromise. The vulnerability's impact is amplified by the fact that the uploaded files are placed directly in the uploads/ directory, eliminating the need for additional privilege escalation or complex attack chains. Attackers can upload PHP files containing malicious code, web shells, or other exploit payloads that persist on the server and can be executed through web browser requests to the upload directory.
From an operational standpoint, this vulnerability creates a severe risk for organizations using affected Pakupaku CMS installations, as it provides attackers with a direct method to establish persistent access to the web server. The implications extend beyond simple code execution to include potential data breaches, system compromise, and the ability to use the compromised server as a launchpad for further attacks within the network. The vulnerability's remote nature means that attackers can exploit it without requiring physical access or local network presence, making it particularly dangerous in environments where web applications are exposed to public internet traffic. This flaw also demonstrates the critical importance of proper file type validation and the principle of least privilege in web application security, as the vulnerability essentially allows attackers to bypass fundamental security controls that should prevent execution of potentially harmful files.
Mitigation strategies for CVE-2007-4640 must address both immediate remediation and long-term architectural improvements to prevent similar vulnerabilities. Organizations should immediately upgrade to Pakupaku CMS versions that address this vulnerability, as the original version is no longer supported and lacks security patches. Technical mitigations include implementing strict file type validation on the server side, rejecting files with dangerous extensions such as .php, .phtml, .php3, .php4, .php5, and .phar, and implementing proper file content inspection to prevent execution of malicious code even if file extensions are properly validated. The implementation of Content Security Policy headers and restricting write permissions on upload directories can further reduce the impact of such vulnerabilities. This vulnerability also aligns with ATT&CK technique T1190, which describes the use of web shells for maintaining access, and highlights the importance of defensive measures such as web application firewalls, file integrity monitoring, and regular security assessments to detect and prevent unauthorized file uploads. Organizations should also implement proper logging and monitoring of file upload activities to detect suspicious behavior and maintain audit trails for incident response purposes.