CVE-2018-9109 in elFinder
Summary
by MITRE
Studio 42 elFinder before 2.1.36 has Directory Traversal via the zipdl() function in elFinder.class.php, resulting in file deletion.
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Analysis
by VulDB Data Team • 02/24/2023
The vulnerability identified as CVE-2018-9109 affects Studio 42 elFinder versions prior to 2.1.36 and represents a critical directory traversal flaw within the zipdl() function located in the elFinder.class.php file. This vulnerability arises from insufficient input validation and sanitization mechanisms that fail to properly restrict user-supplied paths during file download operations. The flaw allows malicious actors to manipulate file paths and potentially delete arbitrary files on the server, creating a significant security risk for systems that rely on this file management utility.
The technical implementation of this vulnerability stems from improper handling of user input within the zipdl() function which processes zip file downloads. When users provide file paths through the download functionality, the application fails to adequately validate or sanitize these inputs, enabling attackers to inject malicious path sequences such as ../ or ..\ that can traverse directory structures. This weakness directly maps to CWE-22, which defines improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The vulnerability exists at the application layer where user-controllable data is processed without proper security controls.
Operationally, this vulnerability presents severe implications for affected systems as it enables unauthorized file deletion capabilities that can compromise entire file systems. An attacker exploiting this vulnerability can potentially remove critical system files, configuration files, or user data, leading to system instability, data loss, or complete system compromise. The impact extends beyond simple file deletion as it can facilitate further attacks by allowing attackers to remove security-related files or create conditions that enable additional exploitation techniques. This vulnerability particularly affects web applications that utilize elFinder for file management, including content management systems, file sharing platforms, and web-based development environments.
The mitigation strategy for CVE-2018-9109 requires immediate implementation of the vendor-provided patch or upgrade to elFinder version 2.1.36 or later, which addresses the directory traversal vulnerability through proper input validation and sanitization. Organizations should implement additional security controls including input validation at multiple layers, restrictive file access controls, and regular security assessments of file management components. The ATT&CK framework categorizes this vulnerability under T1059 Command and Scripting Interpreter and T1078 Valid Accounts, as exploitation typically requires understanding of the file system structure and may involve privilege escalation. System administrators should also consider implementing web application firewalls to monitor and block suspicious path traversal attempts, while maintaining comprehensive logging of file operations for forensic analysis. Regular security audits and vulnerability assessments should be conducted to identify similar weaknesses in other file management utilities and prevent similar incidents from occurring in the future.