CVE-2023-33920 in CP-8031 MASTER MODULE
Summary
by MITRE • 06/13/2023
A vulnerability has been identified in CP-8031 MASTER MODULE (All versions < CPCI85 V05), CP-8050 MASTER MODULE (All versions < CPCI85 V05). The affected devices contain the hash of the root password in a hard-coded form, which could be exploited for UART console login to the device. An attacker with direct physical access could exploit this vulnerability.
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Analysis
by VulDB Data Team • 06/13/2023
The vulnerability identified as CVE-2023-33920 affects critical industrial control systems manufactured by a specific vendor, namely the CP-8031 MASTER MODULE and CP-8050 MASTER MODULE. These devices operate within industrial environments where physical security is paramount, yet they contain a fundamental flaw in their authentication mechanism that undermines system integrity. The affected versions are all prior to CPCI85 V05, indicating this represents a long-standing issue that has persisted across multiple firmware releases without adequate remediation. The vulnerability specifically resides in the device's boot process where a hard-coded hash of the root password is embedded within the system firmware, creating a persistent backdoor mechanism that bypasses normal authentication procedures.
The technical flaw manifests through the improper implementation of authentication credentials within the device firmware, which directly correlates to CWE-259 Use of Hard-coded Password and CWE-798 Use of Hard-coded Credentials. This hard-coded credential exists in a form that can be directly utilized for system access rather than merely being stored as a reference. The vulnerability is particularly dangerous because it allows unauthorized access to the UART console, which provides low-level system access typically reserved for maintenance and administrative functions. The UART console represents a critical attack surface since it provides direct access to the device's operating system, allowing for complete system compromise without requiring network connectivity or traditional authentication methods.
The operational impact of this vulnerability is severe for industrial environments where these modules are deployed, as it creates an unauthenticated access point that can be exploited by attackers with direct physical access to the device. This represents a significant risk to industrial control systems because the attacker can gain root privileges and potentially manipulate system configurations, access sensitive data, or disrupt operations. The vulnerability is particularly concerning in environments where physical security controls are inadequate or where devices are deployed in accessible locations. The fact that this affects all versions prior to CPCI85 V05 suggests that organizations may have been running vulnerable systems for extended periods without awareness of the risk.
The exploitation of this vulnerability requires only physical access to the device, making it particularly dangerous in industrial settings where physical security may not be as stringent as in traditional IT environments. Attackers can connect to the UART console and leverage the hard-coded hash to authenticate as root user, gaining complete administrative control over the device. This aligns with ATT&CK technique T1072 Software Deployment Tools where adversaries use legitimate system tools to gain access, though in this case the tool is the UART console with pre-configured credentials. Organizations should implement immediate mitigation strategies including firmware updates to version CPCI85 V05 or later, physical security measures to prevent unauthorized access to devices, and network segmentation to limit the potential impact of successful exploitation. Additionally, regular security assessments should be conducted to identify other instances of hard-coded credentials within industrial control systems, as this vulnerability represents a broader class of issues that can compromise operational technology environments.