CVE-2018-16238 in DamiCMS
Summary
by MITRE
An issue was discovered in damiCMS V6.0.1. Remote code execution can occur via PHP code in a multipart/form-data POST to the admin.php?s=/Tpl/Update.html URI. For example, this can update the Web/Tpl/default/head.html file.
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Analysis
by VulDB Data Team • 03/19/2020
The vulnerability identified as CVE-2018-16238 resides within damiCMS version 6.0.1, representing a critical remote code execution flaw that fundamentally undermines the security posture of affected systems. This vulnerability manifests through improper input validation and sanitization mechanisms within the content management system's administrative interface, specifically targeting the file upload and template update functionality. The flaw enables attackers to execute arbitrary PHP code on the target server by leveraging a crafted multipart/form-data POST request directed at the admin.php?s=/Tpl/Update.html endpoint, which serves as a direct pathway for template modifications within the system's administrative panel.
The technical exploitation of this vulnerability exploits a fundamental weakness in the application's file handling and validation processes, where user-supplied data is not adequately sanitized before being processed and written to the filesystem. When an attacker submits malicious PHP code within the multipart/form-data payload, the system fails to validate the content against legitimate template code patterns, allowing the malicious code to be written to the Web/Tpl/default/head.html file. This represents a classic path traversal and code injection vulnerability, where the attacker can manipulate the system's template update mechanism to inject executable code that will be executed during subsequent web requests. The vulnerability operates at the intersection of multiple security domains including input validation, file system permissions, and code execution contexts, making it particularly dangerous as it bypasses traditional security controls.
The operational impact of this vulnerability is severe and far-reaching, as it provides attackers with complete control over the affected server and the entire content management system. Once successfully exploited, adversaries can execute arbitrary commands with the privileges of the web server process, potentially leading to full system compromise, data exfiltration, and persistent backdoor establishment. The vulnerability affects not only the specific template files mentioned but could potentially allow attackers to upload additional malicious components, modify existing system files, or establish reverse shells for ongoing access. This type of vulnerability directly aligns with CWE-94, which describes the weakness of executing arbitrary code, and represents a significant deviation from secure coding practices that should prevent untrusted data from being executed as code. The attack vector specifically maps to ATT&CK technique T1190, which covers the use of exploits for code execution, and T1059, which involves executing commands through various interfaces.
Mitigation strategies for CVE-2018-16238 must address both immediate remediation and long-term security hardening measures. The primary recommendation involves applying the vendor-provided security patch or upgrading to a version that resolves the input validation issues in the template update functionality. Organizations should implement strict input validation and sanitization for all user-supplied data, particularly when handling file uploads or template modifications. Additional protective measures include implementing web application firewalls to detect and block suspicious multipart/form-data requests, restricting write permissions on template directories, and implementing proper access controls to limit administrative functionality to trusted users only. The vulnerability also highlights the importance of principle of least privilege, where the web server should operate with minimal necessary permissions, and regular security audits should be conducted to identify similar input validation weaknesses in other parts of the application. Network segmentation and monitoring should be enhanced to detect anomalous file modification patterns that may indicate exploitation attempts, while regular security assessments should be performed to ensure that similar vulnerabilities do not exist in other components of the CMS ecosystem.