CVE-2006-0695 in Ansilove
Summary
by MITRE
Ansilove before 1.03 does not filter uploaded file extensions, which allows remote attackers to execute arbitrary code by uploading arbitrary files with dangerous extensions, then accessing them directly in the upload directory.
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Analysis
by VulDB Data Team • 07/19/2018
The vulnerability identified as CVE-2006-0695 affects Ansilove versions prior to 1.03 and represents a critical file upload security flaw that enables remote code execution through improper file extension validation. This issue stems from the application's failure to properly filter or validate file extensions during the upload process, creating a pathway for attackers to bypass security controls and deploy malicious payloads. The vulnerability specifically targets the file handling mechanism within the application's upload directory functionality, where uploaded files are stored and subsequently accessible through direct web requests.
The technical implementation of this flaw resides in the application's lack of proper input sanitization and validation controls. When users upload files through the Ansilove interface, the system does not perform adequate checks to verify that file extensions match expected patterns or are restricted to safe file types. This absence of validation allows attackers to upload files with extensions such as .php, .asp, .jsp, or other server-side script extensions that could execute code on the web server. The vulnerability operates under the principle of insecure file upload, where the application accepts potentially malicious files without proper security screening, directly violating fundamental security practices for file handling operations.
The operational impact of this vulnerability is severe and encompasses multiple attack vectors that can lead to complete system compromise. Remote attackers can leverage this flaw to upload malicious scripts that execute arbitrary commands on the server, potentially gaining full control over the affected system. The direct access to the upload directory means that once a malicious file is uploaded, it can be executed immediately by accessing its URL, eliminating the need for additional exploitation steps. This vulnerability directly maps to attack techniques described in the attack tree framework, where attackers can progress from initial access through privilege escalation to system compromise through the exploitation of insecure file upload mechanisms. The impact extends beyond simple code execution to include potential data exfiltration, service disruption, and establishment of persistent backdoors within the target environment.
The vulnerability aligns with CWE-434, which specifically addresses "Unrestricted Upload of File with Dangerous Type," and represents a classic example of insufficient input validation and sanitization. This weakness creates a direct pathway for attackers to bypass security controls and execute malicious code through the web application interface. Mitigation strategies should include implementing strict file extension validation, maintaining a whitelist of allowed file types, and ensuring that uploaded files are stored outside the web root directory to prevent direct execution. Additionally, the application should implement proper file type detection beyond simple extension checking, use random or unique filenames for uploaded content, and employ proper access controls to restrict file access. The remediation process must also include comprehensive testing of file upload functionality and implementation of security controls that align with industry best practices for secure file handling as outlined in OWASP secure coding guidelines and NIST cybersecurity frameworks. Organizations should also consider implementing web application firewalls and intrusion detection systems to monitor for suspicious file upload activities and prevent exploitation attempts.