CVE-2021-22720 in C-Bus Toolkit
Summary
by MITRE • 04/13/2021
A CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability exists in C-Bus Toolkit (V1.15.7 and prior) that could allow a remote code execution when restoring a project.
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Analysis
by VulDB Data Team • 04/17/2021
The vulnerability identified as CVE-2021-22720 represents a critical path traversal flaw classified under CWE-22 within the C-Bus Toolkit software version 1.15.7 and earlier. This issue manifests in the project restoration functionality where inadequate input validation permits malicious actors to manipulate file paths and potentially execute arbitrary code on affected systems. The vulnerability stems from insufficient restrictions on pathname inputs during the restoration process, creating an attack surface where remote adversaries can exploit the lack of proper sanitization mechanisms.
The technical implementation of this vulnerability allows attackers to manipulate the restoration procedure by crafting malicious project files that contain directory traversal sequences such as ../ or ..\ in their file paths. When the C-Bus Toolkit processes these crafted inputs without proper validation, it fails to restrict file operations to the intended restricted directories, enabling attackers to write files to arbitrary locations on the target system. This flaw particularly affects the software's project restoration feature, where users might unknowingly trigger the execution of malicious code during normal operational procedures.
Operationally, this vulnerability poses significant risks to organizations utilizing C-Bus Toolkit for building automation and control systems. Remote code execution capabilities can enable attackers to gain full system control, install backdoors, exfiltrate sensitive data, or disrupt critical infrastructure operations. The impact extends beyond simple privilege escalation as the vulnerability can be exploited without authentication, making it particularly dangerous in environments where the toolkit is accessible over networks. Security professionals must consider the potential for lateral movement within networks where such systems are deployed, as compromised toolkit instances could serve as entry points for broader attacks.
The exploitation of this vulnerability aligns with tactics described in the ATT&CK framework under initial access and execution phases, where adversaries leverage software vulnerabilities to establish persistent access. Organizations should implement immediate mitigations including updating to patched versions of C-Bus Toolkit, implementing network segmentation to limit access to affected systems, and monitoring for suspicious file operations during project restoration activities. Additionally, security controls should enforce strict input validation and file path restrictions, while regular security assessments should verify that no unauthorized modifications have occurred in the affected environments. The vulnerability demonstrates the critical importance of proper input validation and access control mechanisms in preventing path traversal attacks that can lead to complete system compromise.