CVE-2018-20792 in Responsive FileManager
Summary
by MITRE
tecrail Responsive FileManager 9.13.4 allows remote attackers to read arbitrary file via path traversal with the path parameter, through the get_file action in ajax_calls.php.
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Analysis
by VulDB Data Team • 05/12/2020
The vulnerability identified as CVE-2018-20792 affects tecrail Responsive FileManager version 9.13.4 and represents a critical path traversal flaw that enables remote attackers to access arbitrary files on the target system. This vulnerability exists within the file management interface's ajax_calls.php script where the path parameter is processed without adequate input validation or sanitization. The specific attack vector involves manipulation of the path parameter through the get_file action, allowing malicious actors to traverse directory structures and retrieve sensitive files that should remain protected. The flaw demonstrates a classic lack of proper access controls and input sanitization mechanisms that are fundamental to secure file handling operations.
The technical implementation of this vulnerability stems from insufficient validation of user-supplied input within the application's file retrieval functionality. When the path parameter is passed to the get_file action in ajax_calls.php, the application fails to properly sanitize or validate the input before using it to construct file paths. This omission creates an opportunity for attackers to craft malicious input sequences that bypass normal file access restrictions and navigate to arbitrary locations within the filesystem. The vulnerability aligns with CWE-22 Path Traversal and CWE-77 Path Traversal, both of which are categorized under the broader family of insecure file handling practices that have been consistently identified as critical security risks across numerous applications and platforms. The attack can be executed without authentication requirements, making it particularly dangerous as it allows unauthenticated remote access to potentially sensitive system files.
The operational impact of this vulnerability extends beyond simple file access, as it can lead to complete system compromise when combined with other exploitation techniques. Attackers can leverage this vulnerability to access configuration files, database credentials, application source code, and potentially system-level files that contain sensitive information. The ability to retrieve arbitrary files through path traversal can provide attackers with detailed insights into the application's architecture, underlying system configuration, and potentially expose credentials or other sensitive data that could facilitate further attacks. This vulnerability also enables attackers to potentially discover other applications or services running on the same system, creating opportunities for lateral movement within network environments. The impact is particularly severe when considering that file managers often have access to directories containing user data, application configurations, and system files that are not typically exposed to public access.
Mitigation strategies for CVE-2018-20792 should focus on implementing proper input validation and sanitization mechanisms to prevent path traversal attacks. The most effective approach involves implementing strict input validation that rejects or normalizes any input containing directory traversal sequences such as ../ or ..\. Additionally, the application should implement proper access controls that restrict file access to authorized users and directories. The implementation of a whitelist approach for file access, where only pre-approved file paths are allowed, provides an additional layer of security that can prevent unauthorized file access. Organizations should also consider implementing proper logging and monitoring to detect attempts to exploit this vulnerability, as well as ensuring that the affected application is updated to a patched version that addresses the path traversal flaw. The vulnerability's classification under the ATT&CK framework would fall under the T1083 File and Directory Discovery technique, indicating that this flaw can be exploited to enumerate system files and directories, which is a common reconnaissance activity in cyber attacks. Regular security assessments and vulnerability scanning should be conducted to identify similar path traversal vulnerabilities in other applications and systems within the organization's infrastructure.