CVE-2019-8908 in WTCMS
Summary
by MITRE
An issue was discovered in WTCMS 1.0. It allows remote attackers to execute arbitrary PHP code by going to the "Setting -> Mailbox configuration -> Registration email template" screen, and uploading an image file, as demonstrated by a .php filename and the "Content-Type: image/gif" header.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 07/11/2023
The vulnerability identified as CVE-2019-8908 affects WTCMS version 1.0 and represents a critical remote code execution flaw that stems from improper input validation and file upload handling within the application's administrative interface. This vulnerability specifically targets the mailbox configuration section where users can manage registration email templates, creating an attack vector that allows remote adversaries to bypass security controls and execute malicious PHP code on the target server. The flaw manifests when an attacker uploads a specially crafted file with a .php extension but uses a Content-Type header indicating it as an image file, effectively circumventing typical file type validation mechanisms that rely on MIME type checking.
The technical implementation of this vulnerability exploits a fundamental weakness in the application's file upload validation process, which fails to properly verify file extensions against their actual content types. This creates a path for attackers to upload PHP scripts disguised as image files, leveraging the web application's trust in the Content-Type header. The vulnerability is classified under CWE-434 as Unrestricted Upload of File with Dangerous Type, which specifically addresses the scenario where applications allow file uploads without proper validation of file types, content, or execution permissions. The attack requires minimal privileges since it targets the administrative interface, and the successful exploitation results in full remote code execution capabilities on the affected server.
The operational impact of this vulnerability extends far beyond simple code execution, as it provides attackers with complete control over the compromised system. Once executed, the malicious PHP code can be used to establish persistent backdoors, exfiltrate sensitive data, escalate privileges, or launch further attacks against network infrastructure. The vulnerability affects the integrity and availability of the web application, potentially leading to complete system compromise and data breaches. According to ATT&CK framework, this vulnerability maps to T1059.007 for PHP and T1566.001 for Phishing, as attackers can leverage this flaw to deploy malicious payloads that enable further reconnaissance and lateral movement within the network environment. The attack surface is particularly concerning because it targets administrative functionality that typically requires authentication, yet the vulnerability allows code execution even when proper authentication is bypassed through the file upload mechanism.
Mitigation strategies for CVE-2019-8908 must address both the immediate vulnerability and implement comprehensive security controls to prevent similar issues in the future. Organizations should immediately apply patches or upgrades to WTCMS 1.0 to address the file upload validation flaw, while implementing strict file type validation that checks both file extensions and actual file content rather than relying solely on MIME type headers. The recommended approach includes implementing a whitelist-based file validation system that only accepts specific, safe file extensions and conducts binary content analysis to verify file types. Additionally, administrative interfaces should enforce strict access controls, implement multi-factor authentication, and ensure that uploaded files are stored outside the web root directory with appropriate execution permissions disabled. Network segmentation and monitoring should be implemented to detect suspicious file upload activities and unauthorized code execution attempts, while regular security audits should validate that all file upload mechanisms properly enforce security controls and maintain compliance with security best practices.