CVE-2020-5514 in Gila
Summary
by MITRE
Gila CMS 1.11.8 allows Unrestricted Upload of a File with a Dangerous Type via .phar or .phtml to the lzld/thumb?src= URI.
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Analysis
by VulDB Data Team • 03/19/2024
The vulnerability identified as CVE-2020-5514 affects Gila CMS version 1.11.8 and represents a critical security flaw that enables unauthorized file upload capabilities with potentially malicious file extensions. This vulnerability specifically targets the lzld/thumb?src= URI endpoint within the content management system, creating an attack vector that allows remote threat actors to upload files with dangerous extensions such as .phar or .phtml. The flaw stems from inadequate input validation and file type checking mechanisms within the application's file handling process, particularly when processing image thumbnail generation requests through the specified URI.
The technical implementation of this vulnerability involves the application's failure to properly validate file extensions and content types when processing requests to the thumbnail generation endpoint. When a user submits a file through the lzld/thumb?src= URI, the system does not adequately verify whether the uploaded file conforms to acceptable security parameters. This allows attackers to upload malicious files with extensions that could execute code on the server, particularly .phar files which are PHP archive files that can contain executable PHP code, or .phtml files which are PHP files that can be executed by the web server. The vulnerability is classified under CWE-434 as Unrestricted Upload of File with Dangerous Type, which directly relates to the lack of proper file validation and type checking in the application's file handling mechanisms.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with a direct path to achieve remote code execution on the affected server. Once an attacker successfully uploads a malicious file through this vulnerability, they can potentially execute arbitrary code with the privileges of the web server process, leading to complete system compromise. This vulnerability can be exploited to establish persistent backdoors, exfiltrate sensitive data, or use the compromised server as a launching point for further attacks within the network infrastructure. The attack surface is particularly concerning because it allows for automated exploitation without requiring authentication, making it a high-priority target for malicious actors seeking to gain unauthorized access to web applications. The vulnerability also aligns with ATT&CK technique T1190 for Exploit Public-Facing Application, as it targets a publicly accessible web endpoint that can be exploited without prior access to the system.
Mitigation strategies for CVE-2020-5514 should focus on implementing robust input validation and file type restrictions at multiple layers of the application architecture. The primary recommendation involves restricting file uploads to only trusted and safe file types, implementing strict file extension validation, and ensuring that uploaded files are stored in a secure location separate from the web root. Additionally, the application should validate file content type and implement proper MIME type checking rather than relying solely on file extensions. Organizations should also consider implementing Web Application Firewall rules to block requests containing dangerous file extensions and ensure that all file uploads are scanned for malicious content. The fix should include proper access controls on the thumbnail generation endpoint to prevent unauthorized file uploads and implement proper logging mechanisms to detect suspicious file upload activities. Regular security updates and patches should be applied to ensure that the CMS remains protected against similar vulnerabilities, while also implementing network segmentation and monitoring to detect potential exploitation attempts.