CVE-2018-8968 in zzcms
Summary
by MITRE
An issue was discovered in zzcms 8.2. user/manage.php allows remote attackers to delete arbitrary files via directory traversal sequences in the oldimg or oldflv parameter in an action=modify request. This can be leveraged for database access by deleting install.lock.
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Analysis
by VulDB Data Team • 01/16/2020
The vulnerability identified as CVE-2018-8968 affects zzcms version 8.2 and represents a critical directory traversal flaw in the user/manage.php script. This weakness allows remote attackers to manipulate file deletion operations through carefully crafted directory traversal sequences in the oldimg or oldflv parameters during action=modify requests. The vulnerability stems from inadequate input validation and sanitization of user-supplied parameters, creating an avenue for attackers to navigate beyond the intended directory structure and target arbitrary files on the server filesystem. The flaw specifically manifests when the application processes file deletion operations without properly restricting the paths that can be accessed, enabling attackers to specify directory traversal sequences such as ../../ or similar patterns that bypass normal file access controls.
The operational impact of this vulnerability extends beyond simple file deletion capabilities and creates a significant security risk for systems running affected versions of zzcms. Attackers can exploit this weakness to delete critical system files including the install.lock file, which serves as a crucial security mechanism that prevents unauthorized database access during the installation process. The deletion of install.lock effectively removes the protection that would normally prevent database access until the installation process is complete, potentially allowing attackers to gain unauthorized access to database credentials and sensitive information. This exploitation pattern aligns with attack techniques described in the ATT&CK framework under T1078 Valid Accounts and T1046 Network Service Scanning, as the vulnerability enables attackers to move laterally within the system and access database resources that should remain protected.
From a technical perspective, this vulnerability maps directly to CWE-22 Improper Limitation of a Pathname to a Restricted Directory, which specifically addresses the issue of insufficient input validation allowing attackers to traverse directory structures beyond intended boundaries. The flaw demonstrates poor secure coding practices where user input is directly incorporated into file system operations without proper sanitization or path validation mechanisms. The vulnerability exists because the application fails to implement proper input validation that would reject or sanitize directory traversal sequences before they are processed in file operations. Security controls such as input filtering, path normalization, and access control checks are either absent or insufficiently implemented, creating a pathway for attackers to manipulate the application's file handling behavior.
The mitigation strategies for this vulnerability should include immediate implementation of proper input validation and sanitization mechanisms that reject or normalize directory traversal sequences in all user-supplied parameters. Organizations should deploy web application firewalls that can detect and block suspicious directory traversal patterns in HTTP requests. The application code must be updated to implement proper path validation that ensures all file operations occur within designated directories and that user input cannot be used to specify paths outside of intended boundaries. Additionally, system administrators should implement proper file access controls and ensure that critical system files such as install.lock are protected from unauthorized deletion. The remediation process should also include regular security audits and code reviews focused on file handling operations to prevent similar vulnerabilities from being introduced in future development cycles. This vulnerability highlights the importance of following secure coding practices and implementing defense-in-depth strategies that protect against path traversal attacks as outlined in industry standards and best practices for web application security.