CVE-2008-0233 in Zero CMS
Summary
by MITRE
Unrestricted file upload vulnerability in Zero CMS 1.0 Alpha and earlier allows remote attackers to bypass intended access restrictions and upload and execute arbitrary files by uploading an avatar file with an accepted Content-Type such as image/jpeg.
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Analysis
by VulDB Data Team • 10/13/2024
The vulnerability identified as CVE-2008-0233 represents a critical unrestricted file upload flaw in Zero CMS version 1.0 Alpha and earlier releases. This vulnerability stems from inadequate input validation and content-type checking mechanisms within the CMS's file upload functionality, specifically affecting the avatar upload feature. The flaw allows remote attackers to circumvent intended access controls and execute arbitrary code on the affected system by leveraging a seemingly legitimate file upload process.
This security weakness operates through a fundamental failure in the application's validation logic where the system accepts files based solely on their Content-Type header rather than implementing comprehensive file type verification. The vulnerability falls under CWE-434, which specifically addresses the improper restriction of file uploads, making it a direct descendant of the well-known weakness pattern for unrestricted file upload attacks. The implementation flaw allows attackers to upload malicious files with extensions that may be interpreted as legitimate image formats, such as .jpg or .jpeg, while the actual file content may contain executable code.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with a direct path to arbitrary code execution on the target system. Once an attacker successfully uploads a malicious file, they can potentially gain full control over the CMS server, leading to data breaches, system compromise, and potential lateral movement within the network. The vulnerability is particularly dangerous because it does not require authentication to exploit, making it a high-impact threat that can be leveraged by anyone with access to the vulnerable CMS instance. According to ATT&CK framework, this vulnerability maps to T1190 - Exploit Public-Facing Application, where the attacker exploits a vulnerability in a publicly accessible application to gain unauthorized access.
The technical exploitation of this vulnerability typically involves crafting a file that appears to be a valid image but contains malicious code within its payload. Attackers often use techniques such as embedding php code within image files or using file extension manipulation to bypass basic security checks. The vulnerability's impact is amplified by the fact that the CMS likely executes uploaded files without proper sandboxing or execution restrictions, creating an ideal environment for malicious code execution. Organizations using affected versions of Zero CMS face significant risk of complete system compromise, data loss, and potential regulatory violations due to the exposure of sensitive information.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security hardening measures. The primary solution involves implementing strict file type validation that checks not only the Content-Type header but also the actual file signature and extension. Organizations should enforce a whitelist approach for allowed file types and ensure that uploaded files are stored in a non-executable directory with proper access controls. Additionally, implementing proper input sanitization, using Content Security Policy headers, and conducting regular security assessments are essential components of a comprehensive defense strategy. The vulnerability also highlights the importance of keeping CMS installations updated and following security best practices such as those outlined in the OWASP Top Ten and NIST Cybersecurity Framework.