CVE-2018-6846 in Z-BlogPHP
Summary
by MITRE
Z-BlogPHP 1.5.1 allows remote attackers to discover the full path via a direct request to zb_system/function/lib/upload.php.
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Analysis
by VulDB Data Team • 02/06/2023
The vulnerability identified as CVE-2018-6846 affects Z-BlogPHP version 1.5.1 and represents a critical information disclosure flaw that exposes the full server path to remote attackers. This issue arises from insufficient input validation and error handling within the upload.php file located in the zb_system/function/lib directory. The vulnerability stems from the application's failure to properly sanitize user inputs or implement adequate access controls when processing direct requests to the upload functionality, creating an avenue for attackers to obtain sensitive system path information.
The technical exploitation of this vulnerability occurs through a straightforward direct request to the zb_system/function/lib/upload.php endpoint without proper authentication or authorization checks. When an attacker sends a crafted request to this specific file, the application inadvertently reveals the complete server path structure through error messages or direct path exposure in the response. This type of information disclosure vulnerability falls under CWE-200 which specifically addresses the exposure of sensitive information through improper error handling or insufficient access controls. The flaw demonstrates poor defensive programming practices where the system fails to implement proper input validation and output sanitization mechanisms.
The operational impact of this vulnerability is significant as it provides attackers with crucial information needed for subsequent exploitation attempts. The disclosed full path enables attackers to understand the server's directory structure, file locations, and potentially identify other vulnerable components within the system. This information can be leveraged for privilege escalation attacks, directory traversal exploits, or to craft more sophisticated attacks targeting specific file locations. The exposure of system paths also violates fundamental security principles of least privilege and defense in depth, as it provides unauthorized access to internal system information that should remain confidential.
Security practitioners should implement immediate mitigations including restricting direct access to sensitive system files through web server configuration, implementing proper input validation and sanitization mechanisms, and ensuring that error messages do not reveal system path information. The ATT&CK framework categorizes this vulnerability under T1083 - File and Directory Discovery, as it enables attackers to gather information about the target system's file structure. Organizations should also deploy web application firewalls to monitor and block suspicious requests to system directories, implement proper access controls and authentication mechanisms, and conduct regular security assessments to identify similar path disclosure vulnerabilities. Additionally, the application should be updated to a patched version that properly handles requests to upload functionality and prevents unauthorized path exposure through error responses or direct file access.