CVE-2018-19404 in YXcms
Summary
by MITRE
In YXcms 1.4.7, protected/apps/appmanage/controller/indexController.php allow remote authenticated Administrators to execute any PHP code by creating a ZIP archive containing a config.php file, hosting the .zip file at an external URL, and visiting index.php?r=appmanage/index/onlineinstall&url= followed by that URL. This is related to the onlineinstall and import functions.
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Analysis
by VulDB Data Team • 04/14/2020
The vulnerability identified as CVE-2018-19404 represents a critical remote code execution flaw within YXcms version 1.4.7, specifically targeting the application's administrative functionality. This security weakness stems from inadequate input validation and improper file handling mechanisms within the protected/apps/appmanage/controller/indexController.php component, which operates under the onlineinstall and import functions. The vulnerability is particularly dangerous because it requires only authenticated administrative access, making it exploitable by malicious actors who have gained administrative credentials or those who can compromise such accounts through social engineering or other means.
The technical exploitation of this vulnerability occurs through a sophisticated attack vector that leverages the application's legitimate file import functionality. An authenticated administrator can craft a malicious ZIP archive containing a config.php file that executes arbitrary PHP code when processed by the vulnerable application. This attack method exploits the trust model inherent in the application's update and installation processes, where external URLs are accepted without proper sanitization or validation. The specific URL parameter format index.php?r=appmanage/index/onlineinstall&url= provides a direct pathway for attackers to deliver their malicious payload, effectively bypassing normal security controls that would typically prevent arbitrary code execution.
The operational impact of this vulnerability extends far beyond simple code execution, as it provides attackers with complete administrative control over the affected system. Once exploited, the malicious PHP code can perform any action permitted by the application's administrative privileges, including data exfiltration, system modification, privilege escalation, and persistence establishment. The vulnerability's location within the application management controller means that successful exploitation can compromise not just the web application itself but potentially the entire underlying server infrastructure, depending on the application's permissions and the server's configuration. This represents a severe compromise of the application's integrity and confidentiality, as attackers can manipulate or destroy application data while maintaining persistent access.
The vulnerability aligns with CWE-434, which addresses the insecure handling of file uploads and the improper validation of file types and contents. It also maps to ATT&CK technique T1059, specifically the execution of malicious code through web shells or command injection, and T1078, which covers legitimate credentials use for unauthorized access. The attack requires minimal technical expertise to execute, making it particularly dangerous for organizations that do not maintain robust monitoring and access control measures. Organizations should implement immediate mitigations including patching the application to version 1.4.8 or later, implementing strict input validation for all URL parameters, and establishing network-level restrictions on external file access. Additionally, organizations should conduct comprehensive security audits of their administrative interfaces, implement multi-factor authentication for administrative accounts, and deploy web application firewalls to detect and block suspicious URL parameter patterns. The vulnerability demonstrates the critical importance of validating all user-supplied inputs and implementing defense-in-depth strategies to prevent privilege escalation attacks.