CVE-2018-18086 in EmpireCMS
Summary
by MITRE
EmpireCMS v7.5 has an arbitrary file upload vulnerability in the LoadInMod function in e/class/moddofun.php, exploitable by logged-in users.
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Analysis
by VulDB Data Team • 04/01/2020
The vulnerability CVE-2018-18086 represents a critical arbitrary file upload flaw in EmpireCMS version 7.5 that resides within the LoadInMod function located in the e/class/moddofun.php file. This vulnerability specifically affects authenticated users who possess valid login credentials, creating a significant security risk for content management system administrators and users who maintain web applications built on this platform. The flaw enables attackers with legitimate accounts to upload malicious files to the server, potentially leading to complete system compromise. The vulnerability stems from insufficient input validation and sanitization mechanisms that fail to properly verify file types and contents before processing uploads. This weakness directly maps to CWE-434, which categorizes insecure file upload handling as a critical security concern in web applications. The attack vector requires minimal privileges since only a logged-in user account is necessary to exploit the vulnerability, making it particularly dangerous in environments where user access is not strictly controlled or monitored.
The technical implementation of this vulnerability allows authenticated users to bypass normal file upload restrictions through the LoadInMod function, which processes module-related file operations without adequate validation of uploaded file extensions or content types. When a user uploads a file through this function, the system fails to perform proper checks to ensure that only legitimate files are accepted, creating an opportunity for attackers to upload malicious scripts or executable files that can be executed on the web server. The lack of proper file type filtering and content verification mechanisms means that attackers can potentially upload php files, shell scripts, or other malicious payloads that can be executed within the context of the web application. This vulnerability aligns with ATT&CK technique T1190, which describes the use of compromised accounts to establish persistence and execute malicious code on target systems. The flaw essentially creates a backdoor opportunity where legitimate users can be exploited to gain unauthorized access to server resources and potentially escalate privileges to full system control.
The operational impact of CVE-2018-18086 extends beyond simple unauthorized file uploads, as it can lead to complete system compromise and data breaches. Once an attacker successfully exploits this vulnerability, they can execute arbitrary code on the web server, potentially gaining access to sensitive user data, database credentials, and system files. The vulnerability can be leveraged to establish persistent access to the compromised system, allowing attackers to maintain control over the web application and potentially use it as a pivot point for attacking other systems within the network. Organizations using EmpireCMS v7.5 are particularly vulnerable since this version lacks proper input validation mechanisms that would normally prevent malicious file uploads. The risk is amplified by the fact that this vulnerability can be exploited by users who already have legitimate access to the system, making detection more difficult and potentially allowing attackers to remain undetected for extended periods. Security professionals should consider this vulnerability as a high-priority threat that requires immediate remediation to prevent potential data loss, service disruption, and regulatory compliance violations.
Organizations should implement immediate mitigation strategies to address this vulnerability, including applying the latest security patches provided by EmpireCMS developers, implementing strict file upload validation mechanisms, and conducting thorough security audits of their web applications. The recommended approach involves disabling or restricting the LoadInMod function for users who do not require module-related file operations, implementing file type whitelisting, and monitoring file upload activities for suspicious behavior. Security teams should also consider implementing web application firewalls and intrusion detection systems to monitor for exploitation attempts. Additionally, organizations should conduct regular security assessments and penetration testing to identify similar vulnerabilities in their web applications. The vulnerability demonstrates the importance of proper input validation and the principle of least privilege in web application security, as the flaw could have been prevented through proper access controls and file handling procedures. Organizations should also review their user access policies to ensure that only authorized personnel have the necessary privileges to perform file upload operations, thereby reducing the attack surface for this and similar vulnerabilities.