CVE-2018-18950 in KindEditor
Summary
by MITRE
KindEditor through 4.1.11 has a path traversal vulnerability in php/upload_json.php. Anyone can browse a file or directory in the kindeditor/attached/ folder via the path parameter without authentication.
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Analysis
by VulDB Data Team • 06/04/2023
The vulnerability identified as CVE-2018-18950 represents a critical path traversal flaw within KindEditor version 4.1.11 and earlier, specifically affecting the php/upload_json.php component. This issue stems from inadequate input validation and sanitization mechanisms that fail to properly restrict file paths, allowing unauthorized users to access arbitrary files or directories within the kindeditor/attached/ folder structure. The vulnerability exists due to the application's failure to properly validate the path parameter, which is directly used in file operations without sufficient sanitization or access control measures.
The technical implementation of this vulnerability occurs through the manipulation of the path parameter in the upload_json.php script, which processes file upload requests. When an attacker submits a crafted path value containing directory traversal sequences such as ../ or ..\, the application processes these sequences without proper validation, enabling access to files outside the intended upload directory. This flaw falls under CWE-22, which specifically addresses path traversal vulnerabilities, and demonstrates a classic example of insufficient input validation that allows attackers to manipulate file system access controls. The vulnerability is particularly dangerous because it operates without requiring any authentication, making it accessible to anyone who can reach the affected endpoint.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to access sensitive files that may contain configuration data, user credentials, or application source code. An attacker could potentially browse directories to discover system files, configuration files, or even access other applications running on the same server. This vulnerability is particularly concerning in web applications where the attached folder may contain user-uploaded content, system logs, or other sensitive materials that should remain protected from unauthorized access. The lack of authentication requirements means that this vulnerability can be exploited immediately upon discovery, without the need for additional credentials or privilege escalation.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1083, which covers file and directory discovery, and demonstrates how path traversal vulnerabilities can be leveraged to gain unauthorized access to system resources. The impact is amplified when considering that the vulnerability affects a widely used rich text editor component, meaning that numerous web applications may be vulnerable if they incorporate this version of KindEditor. Organizations should implement immediate mitigations including input validation, proper path sanitization, and access control restrictions. The recommended remediation involves implementing strict input validation on the path parameter, ensuring that all file operations occur within designated directories, and implementing proper authentication checks for file access operations. Additionally, organizations should consider implementing web application firewalls and monitoring for suspicious path traversal attempts to detect potential exploitation attempts.