CVE-2017-9364 in BigTree
Summary
by MITRE
Unrestricted File Upload exists in BigTree CMS through 4.2.18: if an attacker uploads an 'xxx.pht' or 'xxx.phtml' file, they could bypass a safety check and execute any code.
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Analysis
by VulDB Data Team • 12/07/2022
The vulnerability identified as CVE-2017-9364 represents a critical unrestricted file upload flaw in BigTree CMS versions up to 4.2.18. This security weakness stems from inadequate input validation and sanitization mechanisms within the content management system's file upload functionality. The vulnerability specifically allows attackers to bypass existing safety checks by exploiting the system's handling of file extensions, particularly those ending with .pht or .phtml suffixes. These file extensions are commonly associated with php files and can execute server-side code when processed by web servers configured to handle such extensions.
The technical exploitation of this vulnerability occurs through a combination of insufficient file type validation and weak security controls in the upload process. When an attacker uploads a file with extensions like .pht or .phtml, the system fails to properly validate these extensions against its security policies, allowing malicious files to be stored on the server. This bypass of safety checks creates a path for remote code execution, as these file types are typically interpreted as executable scripts by web servers. The vulnerability aligns with CWE-434 which categorizes unrestricted upload of files with dangerous types, and represents a direct violation of secure coding practices for file handling operations.
The operational impact of this vulnerability is severe and far-reaching for organizations using affected BigTree CMS versions. Successful exploitation enables attackers to execute arbitrary code on the target server, potentially leading to complete system compromise. Attackers can upload malicious scripts that may establish backdoors, exfiltrate sensitive data, or use the compromised server as a launching point for further attacks within the network. The vulnerability affects the integrity and confidentiality of the entire content management infrastructure, potentially exposing user data, administrative credentials, and other sensitive information stored within the CMS. This represents a critical threat to organizational security posture and can result in significant financial and reputational damage.
Organizations should immediately implement multiple layers of mitigation strategies to address this vulnerability. The primary remediation involves updating to BigTree CMS version 4.2.19 or later, which includes proper file extension validation and enhanced security controls. Additionally, administrators should implement strict file type validation at both the application and web server levels, ensuring that only approved file extensions are accepted. Network-level protections such as web application firewalls should be configured to block suspicious file upload attempts. The mitigation strategy should also include restricting upload permissions to authenticated users only and implementing proper file access controls. This vulnerability demonstrates the importance of adhering to ATT&CK framework techniques such as T1190 for exploiting vulnerabilities in web applications and T1059 for executing code through web shells, emphasizing the need for comprehensive security controls that address both prevention and detection of such attacks.