CVE-2018-9134 in DeDeCMS
Summary
by MITRE
file_manage_control.php in DedeCMS 5.7 has CSRF in an fmdo=rename action, as demonstrated by renaming an arbitrary file under uploads/userup to a .php file under the web root to achieve PHP code execution. This uses the oldfilename and newfilename parameters.
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Analysis
by VulDB Data Team • 02/06/2021
The vulnerability identified as CVE-2018-9134 resides within DedeCMS version 5.7's file_manage_control.php component, representing a critical cross-site request forgery flaw that enables unauthorized file manipulation. This vulnerability specifically affects the fmdo=rename action within the file management functionality, creating a pathway for attackers to execute malicious code through improper input validation and lack of proper authentication checks. The flaw manifests when an attacker can manipulate the oldfilename and newfilename parameters to rename files within the uploads/userup directory, potentially allowing the creation of PHP files in the web root directory. This represents a severe security weakness that directly violates the principle of least privilege and proper access controls as outlined in cybersecurity best practices.
The technical implementation of this vulnerability exploits the absence of anti-CSRF tokens and proper session validation mechanisms within the file management interface. When a user performs file operations through the web interface, the system fails to verify that the request originates from an authenticated and authorized user session. The rename functionality does not validate the referer header or implement proper CSRF protection measures, making it susceptible to exploitation through social engineering or by tricking authenticated users into visiting malicious websites. The attack vector specifically targets the file renaming process where the oldfilename and newfilename parameters are directly processed without adequate sanitization or verification of the user's intent. This vulnerability aligns with CWE-352, which defines Cross-Site Request Forgery as a weakness where the application fails to validate that requests originate from legitimate sources.
The operational impact of this vulnerability extends beyond simple file manipulation to encompass full code execution capabilities within the target web server environment. By renaming a file from the uploads/userup directory to a .php file in the web root, an attacker can execute arbitrary PHP code, potentially leading to complete system compromise. This allows for persistent backdoor access, data exfiltration, and further lateral movement within the network infrastructure. The vulnerability demonstrates the critical importance of input validation and proper access control implementation, as it enables attackers to escalate privileges and bypass security controls that should normally prevent such operations. Organizations utilizing DedeCMS 5.7 are particularly vulnerable to this attack, as the flaw exists in the core file management functionality that is frequently accessed by legitimate users.
Mitigation strategies for CVE-2018-9134 should prioritize immediate implementation of proper anti-CSRF token mechanisms, ensuring that all file management operations require valid session tokens and referer validation. Security patches should be applied to update DedeCMS to versions that address this vulnerability, while administrators should implement proper input sanitization and validation for all file operations. Network segmentation and access controls should be enforced to limit file system access, and regular security audits should verify that proper authentication mechanisms are in place for all administrative functions. The remediation approach should follow the ATT&CK framework's guidance for mitigating privilege escalation attacks, focusing on reducing the attack surface through proper access controls and implementing multi-factor authentication for administrative functions. Additionally, monitoring systems should be configured to detect unusual file manipulation patterns that could indicate exploitation attempts, as this vulnerability represents a common entry point for attackers seeking persistent access to web applications.