CVE-2006-4617 in vtiger
Summary
by MITRE
Unrestricted file upload vulnerability in fileupload.html in vtiger CRM 4.2.4, and possibly earlier versions, allows remote attackers to upload and execute arbitrary files with executable extensions in the /cashe/mails folder.
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Analysis
by VulDB Data Team • 08/03/2018
The vulnerability identified as CVE-2006-4617 represents a critical security flaw in vtiger CRM version 4.2.4 and potentially earlier releases, specifically within the fileupload.html component. This issue falls under the category of unrestricted file upload vulnerabilities, which are particularly dangerous because they allow unauthorized users to bypass normal file validation mechanisms and upload malicious content directly to the target system. The vulnerability is particularly concerning as it affects a core business application that many organizations rely on for customer relationship management and business operations.
The technical flaw manifests in the file upload functionality where the application fails to properly validate or sanitize file extensions and content before storing uploaded files in the /cashe/mails folder. This lack of proper input validation means that attackers can upload files with executable extensions such as .php, .asp, .jsp, or other potentially harmful file types that could be executed within the web server context. The vulnerability stems from insufficient server-side validation controls that should normally restrict file uploads to safe, non-executable formats only. According to CWE guidelines, this maps to CWE-434 which describes the improper restriction of uploads to a restricted directory, making it a well-documented and dangerous class of vulnerability.
The operational impact of this vulnerability is severe and multifaceted, as it provides remote attackers with a direct path to execute arbitrary code on the affected system. Once an attacker successfully uploads a malicious file, they can potentially gain complete control over the web server hosting vtiger CRM, allowing for data theft, system compromise, or further network infiltration. The attack surface is expanded by the fact that the uploaded files are stored in a location that may be accessible via web requests, enabling the attacker to execute their payload directly through a web browser. This vulnerability aligns with several ATT&CK techniques including T1190 for Exploit Public-Facing Application and T1059 for Command and Scripting Interpreter, demonstrating how attackers can leverage such flaws to establish persistent access and execute malicious code.
Organizations affected by this vulnerability should immediately implement multiple layers of mitigation strategies to protect their systems. The most critical immediate action involves patching the application to the latest available version that contains proper file upload validation controls. Additionally, administrators should implement strict file type validation on the server side, ensuring that only safe file extensions are accepted for upload and that uploaded files are stored outside of web-accessible directories. Network-level protections including firewall rules and web application firewalls can help detect and block suspicious upload attempts. The principle of least privilege should be applied to the file upload functionality, limiting the permissions of the web server account and implementing proper access controls. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other applications and ensure that file upload mechanisms are properly secured. Organizations should also consider implementing file content validation in addition to extension checking, as attackers may attempt to bypass restrictions by using legitimate file extensions with malicious content.