CVE-2021-33014 in KR C4
Summary
by MITRE • 05/26/2022
An attacker can gain VxWorks Shell after login due to hard-coded credentials on a KUKA KR C4 control software for versions prior to 8.7 or any product running KSS.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 06/01/2022
The vulnerability identified as CVE-2021-33014 represents a critical authentication flaw affecting KUKA KR C4 control software and related products utilizing the KSS (KUKA Software Suite) platform. This weakness stems from the inclusion of hard-coded credentials within the system architecture, creating a persistent backdoor that allows unauthorized access to the VxWorks shell environment. The vulnerability specifically impacts versions prior to 8.7 of the KUKA KR C4 control software, though any product running the KSS platform may be susceptible to similar exposure. The presence of hardcoded credentials in industrial control systems constitutes a fundamental security failure that directly violates established security principles and best practices for credential management.
The technical implementation of this vulnerability involves the embedding of default usernames and passwords within the software binaries or configuration files of the affected systems. These hard-coded credentials remain unchanged regardless of system configuration or security updates, providing attackers with consistent access paths to the underlying VxWorks operating system shell. The VxWorks shell represents a critical attack surface since it provides direct command execution capabilities and system-level access to the industrial control environment. This flaw operates at the application layer and can be exploited through network-based attacks, requiring no additional privileges or complex exploitation techniques beyond the initial discovery of the hardcoded credentials. The vulnerability aligns with CWE-798, which specifically addresses the use of hard-coded credentials, and represents a classic example of poor security configuration management in industrial control systems.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential disruption of critical manufacturing processes, data compromise, and possible physical system damage. Industrial control systems running affected software versions become immediately vulnerable to attackers who can execute arbitrary commands, modify control parameters, or manipulate production processes. The consequences are particularly severe in manufacturing environments where precise control over machinery and processes is essential for safety and operational continuity. Attackers leveraging this vulnerability could potentially cause production line shutdowns, quality control issues, or even physical safety hazards if critical machinery is compromised. The vulnerability's persistence across system updates and reboots makes it especially dangerous as it cannot be resolved through standard patching procedures without complete software replacement or reinstallation.
Mitigation strategies for CVE-2021-33014 require immediate action to address the hardcoded credential exposure. Organizations should prioritize upgrading to KUKA software versions 8.7 or later, which contain fixes for this vulnerability. System administrators must conduct thorough inventory assessments to identify all affected devices and verify that no hardcoded credentials remain in operational systems. Network segmentation and access control measures should be implemented to limit exposure of industrial control systems to external networks. Regular security audits and penetration testing should be conducted to identify similar hardcoded credential issues throughout industrial control environments. The vulnerability demonstrates the importance of following the principle of least privilege and implementing proper credential lifecycle management in industrial settings. This case study reinforces the necessity of adhering to industrial cybersecurity frameworks such as NIST SP 800-82 and IEC 62443 standards that emphasize secure configuration management and credential protection in critical infrastructure environments.