CVE-2018-3758 in express-cart Module
Summary
by MITRE
Unrestricted file upload (RCE) in express-cart module before 1.1.7 allows a privileged user to gain access in the hosting machine.
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Analysis
by VulDB Data Team • 02/17/2020
The CVE-2018-3758 vulnerability represents a critical security flaw in the express-cart module affecting versions prior to 1.1.7. This vulnerability stems from an unrestricted file upload mechanism that permits authenticated users to upload arbitrary files to the target system. The flaw occurs within the module's file handling logic where proper validation and sanitization of uploaded files are absent or insufficient. The vulnerability classification aligns with CWE-434 which specifically addresses "Unrestricted Upload of File with Dangerous Type" and represents a significant concern for web application security. The issue creates a pathway for privilege escalation attacks where a malicious user with legitimate access can leverage this vulnerability to execute arbitrary code on the hosting machine.
The technical implementation of this vulnerability exploits the lack of proper file type validation and content inspection mechanisms within the express-cart module. When a user uploads a file, the system fails to verify the file extension, MIME type, or file content against a whitelist of acceptable formats. This allows attackers to upload malicious files such as php shell scripts, javascript webshells, or other executable payloads that can be executed within the context of the web server. The vulnerability essentially creates a backdoor within the web application that can be exploited to gain persistent access to the underlying hosting infrastructure. The attack vector typically involves a user with legitimate privileges uploading a crafted file that gets processed and stored on the server without proper security checks.
The operational impact of CVE-2018-3758 extends beyond simple unauthorized access, as it enables a wide range of malicious activities including but not limited to remote code execution, data exfiltration, privilege escalation, and system compromise. Once an attacker successfully exploits this vulnerability, they can establish persistent access to the hosting environment, potentially leading to full system compromise. The vulnerability creates a persistent threat vector that can be leveraged for long-term reconnaissance, lateral movement within the network, and data theft. Organizations running vulnerable versions of express-cart are exposed to significant risk as the attacker can use the compromised system as a launching point for further attacks against other systems within the network infrastructure. This vulnerability directly impacts the CIA triad by compromising confidentiality, integrity, and availability of the affected systems.
The mitigation strategy for CVE-2018-3758 requires immediate implementation of the vendor-provided patch version 1.1.7 or later which addresses the unrestricted file upload issue through proper file validation mechanisms. Organizations should implement multiple layers of defense including input validation, file type restriction, content inspection, and proper file storage practices. The recommended approach involves enforcing strict file extension whitelisting, implementing MIME type checking, and using secure file upload directories with restricted permissions. Additionally, organizations should consider implementing web application firewalls, monitoring for suspicious file upload activities, and conducting regular security assessments of their web applications. The vulnerability demonstrates the importance of following secure coding practices as outlined in the OWASP Top Ten and aligns with ATT&CK technique T1059.007 for command and scripting interpreter which can be leveraged through the RCE capability provided by this vulnerability. Proper security configuration and regular patch management are essential to prevent exploitation of this class of vulnerabilities that represent a common attack surface in web applications.