CVE-2018-13056 in zzcms
Summary
by MITRE
An issue was discovered on zzcms 8.3. There is a vulnerability at /user/del.php that can delete any file by placing its relative path into the zzcms_main table and then making an img add request. This can be leveraged for database access by deleting install.lock.
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Analysis
by VulDB Data Team • 02/23/2020
The vulnerability identified as CVE-2018-13056 resides within zzcms version 8.3, specifically targeting the file deletion functionality at /user/del.php. This represents a critical security flaw that enables unauthorized file removal through manipulation of the zzcms_main database table. The vulnerability stems from insufficient input validation and improper access controls that allow attackers to construct malicious requests capable of executing arbitrary file deletion operations. The flaw operates by exploiting the database interaction mechanism where an attacker can inject a relative file path into the zzcms_main table and subsequently trigger an image addition request that executes the deletion operation.
This vulnerability falls under the category of improper input validation and privilege escalation as classified by CWE-20, which addresses weaknesses in the validation of input data that can lead to arbitrary code execution or unauthorized access. The attack vector leverages the application's trust in database-stored paths without proper verification of their legitimacy or safety. The specific implementation flaw allows for path traversal and arbitrary file deletion through database manipulation rather than direct file system access, making it particularly insidious as it operates through the application's legitimate database interaction channels.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with the capability to delete critical system files including the install.lock file that typically prevents unauthorized database access during installation processes. This deletion can potentially expose database credentials or configuration files, leading to full system compromise and unauthorized access to sensitive data. The vulnerability creates a persistent backdoor condition where attackers can repeatedly exploit the flaw to maintain access and escalate privileges. Additionally, the ability to delete arbitrary files can result in complete system corruption, application downtime, and data loss, making it a critical concern for organizations relying on zzcms platforms.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1078.004 which covers valid accounts usage through legitimate credentials, and T1486 which addresses data encryption for ransomware. The exploitation pathway demonstrates how database manipulation can be used to bypass traditional file system security controls and achieve unauthorized access. Organizations should implement comprehensive input validation controls, enforce proper access controls on database tables, and implement file system monitoring to detect unauthorized deletion activities. The vulnerability also highlights the importance of principle of least privilege implementation where database access should be restricted to prevent manipulation of critical system paths and files.
Mitigation strategies should include immediate patching of the zzcms application to version 8.4 or later where this vulnerability has been addressed, implementing strict input validation on all database interactions, and establishing proper file system permissions that prevent unauthorized deletion operations. Network segmentation and monitoring solutions should be deployed to detect anomalous database access patterns and file deletion activities. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in database-driven applications. The vulnerability also underscores the need for secure coding practices that prevent injection attacks and ensure proper validation of all user-supplied data before database manipulation occurs, particularly in applications that handle user-generated content or administrative functions through database interactions.