CVE-2019-18871 in Remote Kiln Control
Summary
by MITRE
A path traversal in debug.php accessed via default.php in Blaauw Remote Kiln Control through v3.00r4 allows an authenticated attacker to upload arbitrary files, leading to arbitrary remote code execution.
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Analysis
by VulDB Data Team • 05/08/2020
The vulnerability identified as CVE-2019-18871 represents a critical path traversal flaw within the Blaauw Remote Kiln Control system version 3.00r4 and earlier. This vulnerability exists in the interaction between default.php and debug.php components, creating an exploitable condition that allows authenticated attackers to bypass normal file upload restrictions. The flaw stems from insufficient input validation and inadequate sanitization of file paths, enabling malicious actors to manipulate the application's file handling mechanisms through carefully crafted requests.
The technical implementation of this vulnerability involves a path traversal attack that exploits weak security controls in the file upload functionality. When an authenticated user accesses the debug.php script through the default.php interface, the application fails to properly validate the file paths being processed. This allows an attacker to manipulate the upload destination by inserting directory traversal sequences such as ../ or ..\ into the file path parameters. The vulnerability is particularly dangerous because it operates within the context of an authenticated session, meaning that an attacker must first establish valid credentials but does not require elevated privileges to exploit the flaw.
The operational impact of this vulnerability extends beyond simple file upload capabilities to encompass full remote code execution privileges. Once an attacker successfully exploits the path traversal condition, they can upload malicious files to arbitrary locations within the application's directory structure. These uploaded files can then be executed by the web server, providing attackers with complete control over the affected system. The implications include potential data theft, system compromise, and the ability to establish persistent access points within the network environment. This vulnerability directly violates security principles outlined in the CWE-22 category for path traversal and aligns with ATT&CK techniques focusing on command and control through web shell deployment.
Organizations utilizing Blaauw Remote Kiln Control systems must implement immediate mitigations to address this vulnerability. The primary remediation involves implementing proper input validation and sanitization of all file path parameters within the application's file handling routines. Security controls should enforce strict file path validation that prevents directory traversal sequences from being processed. Additionally, implementing proper access controls and privilege separation ensures that even if exploitation occurs, attackers cannot escalate their privileges or access unauthorized system resources. The fix should include validating file upload destinations against a whitelist of allowed directories and implementing proper file type restrictions to prevent execution of malicious code. Organizations should also consider implementing network segmentation and monitoring solutions to detect suspicious file upload activities that may indicate exploitation attempts. This vulnerability demonstrates the critical importance of secure coding practices and proper input validation in preventing path traversal attacks that can lead to complete system compromise.