CVE-2023-41255 in ctrlX HMI Web Panel WR21
Summary
by MITRE • 10/25/2023
The vulnerability allows an unprivileged user with access to the subnet of the TPC-110W device to gain a root shell on the device itself abusing the lack of authentication of the ‘su’ binary file installed on the device that can be accessed through the ADB (Android Debug Bridge) protocol exposed on the network.
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Analysis
by VulDB Data Team • 11/17/2023
The CVE-2023-41255 vulnerability represents a critical security flaw in the TPC-110W device that exposes a path to full system compromise through improper authentication mechanisms. This vulnerability specifically targets the device's Android Debug Bridge implementation, which inadvertently exposes the su binary without proper authentication checks. The flaw exists within the device's network configuration where ADB protocol remains accessible to unauthorized network entities, creating an attack surface that allows unprivileged users to escalate privileges to root level access. The TPC-110W device, designed for industrial or embedded applications, suffers from a fundamental security misconfiguration that violates basic principle of least privilege by permitting direct access to system administrative functions through an exposed debugging interface.
The technical exploitation of this vulnerability relies on the absence of authentication controls for the su binary, which is a standard Unix/Linux utility designed to switch user contexts and grant administrative privileges. When the ADB protocol is exposed on the network, attackers can leverage this interface to execute commands directly on the device, bypassing normal authentication mechanisms that should prevent unauthorized privilege escalation. The su binary, when accessible without proper authentication, allows any network-accessible user to assume root privileges, effectively granting complete control over the device's operating system, file system, and all associated services. This flaw operates at the application layer and can be exploited through standard network reconnaissance and exploitation techniques that do not require physical access to the device.
The operational impact of CVE-2023-41255 is severe and far-reaching, particularly in environments where these devices are deployed for industrial control systems or network infrastructure monitoring. Once an attacker gains root access, they can modify system configurations, install malicious software, exfiltrate sensitive data, or disrupt device operations entirely. The vulnerability creates a persistent backdoor that can be maintained across device reboots and system updates, making it particularly dangerous for long-term deployments. The attack vector requires only network access to the device's subnet, meaning that adversaries can exploit this vulnerability from remote locations without requiring physical presence or specialized equipment. This makes the device particularly vulnerable in unsecured network environments or when proper network segmentation is not implemented.
Security mitigation strategies for CVE-2023-41255 must address both the immediate exposure of ADB services and the underlying authentication flaws in the su binary implementation. The primary recommendation involves disabling the ADB protocol entirely on production devices or restricting access through network firewalls to only trusted IP addresses. Organizations should implement proper network segmentation to isolate these devices from general network traffic and apply access control lists that prevent unauthorized network discovery and access. Additionally, the su binary should be configured with appropriate authentication controls, and regular security audits should verify that debugging interfaces are not exposed to unauthorized network access. This vulnerability aligns with CWE-284 which addresses improper access control in software systems, and represents a clear violation of the principle of least privilege as outlined in the MITRE ATT&CK framework under privilege escalation techniques. Organizations should also consider implementing intrusion detection systems to monitor for suspicious ADB protocol usage and establish regular patching procedures to address similar authentication flaws that may exist in other embedded systems.