CVE-2017-17992 in Biometric Shift Employee Management System
Summary
by MITRE
Biometric Shift Employee Management System allows Arbitrary File Download via directory traversal sequences in the index.php form_file_name parameter in a download_form action.
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Analysis
by VulDB Data Team • 12/18/2019
The CVE-2017-17992 vulnerability resides within the Biometric Shift Employee Management System, a software solution designed for workforce management and attendance tracking. This particular flaw represents a directory traversal attack vector that enables unauthorized access to sensitive system files through manipulation of the index.php form_file_name parameter. The vulnerability specifically manifests during the download_form action, where the application fails to properly validate user input, allowing malicious actors to craft requests that traverse directory structures and access files outside the intended download scope. The affected parameter form_file_name operates as a critical input point where directory traversal sequences can be injected, potentially exposing system configuration files, database credentials, or other sensitive data stored within the application's file hierarchy.
The technical exploitation of this vulnerability stems from insufficient input validation and sanitization mechanisms within the application's file handling routines. When the download_form action processes the form_file_name parameter, it does not adequately filter or sanitize the input to prevent directory traversal sequences such as ../ or ..\ that would normally be blocked by proper path validation. This allows attackers to manipulate the file path to access files in parent directories or even system-level files that should remain inaccessible to end users. The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. Such flaws typically occur when applications fail to properly validate or sanitize user-supplied input before using it in file system operations, creating opportunities for attackers to access unauthorized resources.
The operational impact of CVE-2017-17992 extends beyond simple unauthorized file access, potentially compromising the entire system security posture. An attacker exploiting this vulnerability could gain access to sensitive employee data, system configuration files, database connection strings, or even application source code that might reveal additional security weaknesses. The ability to download arbitrary files through directory traversal creates a significant risk for organizations relying on this biometric management system, as it could lead to data breaches, system compromise, or facilitate further attacks within the network. This vulnerability particularly affects organizations with limited network segmentation, where access to such systems might provide a foothold for lateral movement. The attack vector represents a classic privilege escalation opportunity that can be leveraged in conjunction with other vulnerabilities to achieve more comprehensive system compromise, aligning with ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting through file system access.
Mitigation strategies for CVE-2017-17992 should focus on implementing robust input validation and sanitization mechanisms within the application's file handling processes. Organizations should immediately apply the vendor-provided patches or updates that address the directory traversal vulnerability in the download_form action. Additionally, implementing proper path validation that rejects or strips directory traversal sequences from user input can prevent exploitation of this class of vulnerability. Network segmentation and access controls should be enforced to limit exposure of the vulnerable system to untrusted networks or users. Regular security audits should include testing for similar path traversal vulnerabilities across all web applications, particularly those handling file operations. The implementation of web application firewalls and input validation rules specifically designed to detect and block directory traversal attempts can provide additional defense in depth. Organizations should also consider implementing principle of least privilege for file system access, ensuring that the application only has access to necessary directories and files. Security monitoring should be enhanced to detect unusual file access patterns or attempts to access system-level files that would normally be restricted to authorized personnel only.