CVE-2021-34591 in CC612
Summary
by MITRE • 04/27/2022
In Bender/ebee Charge Controllers in multiple versions are prone to Local privilege Escalation. An authenticated attacker could get root access via the suid applications socat, ip udhcpc and ifplugd.
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Analysis
by VulDB Data Team • 04/30/2022
The vulnerability identified as CVE-2021-34591 affects Bender/ebee Charge Controllers across multiple firmware versions, presenting a critical local privilege escalation flaw that enables authenticated attackers to obtain root access. This security weakness stems from the improper configuration of setuid (suid) applications within the device's operating system, specifically targeting three critical binaries: socat, ip udhcpc, and ifplugd. These applications are designed to run with elevated privileges to perform system-level operations, but their misconfiguration creates a pathway for unauthorized privilege elevation. The vulnerability represents a significant concern for industrial control systems and embedded devices that rely on these charge controllers for power management and monitoring purposes.
The technical flaw manifests through the improper implementation of the setuid bit on critical system binaries, which should only execute with root privileges when invoked by specific legitimate processes. In this case, the socat binary allows arbitrary command execution when invoked with elevated privileges, while ip udhcpc and ifplugd contain exploitable code paths that can be leveraged to gain root access through privilege escalation techniques. The attackers need only authenticate to the system with valid user credentials, as the vulnerability exists in the privilege escalation mechanism rather than requiring physical access or more sophisticated attack vectors. This configuration error creates an attack surface where any authenticated user can exploit the misconfigured setuid binaries to execute arbitrary commands with root privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it compromises the integrity and confidentiality of the entire charge controller system. An attacker with root access can modify system configurations, install malicious software, monitor network traffic, and potentially gain access to other connected systems within the same network segment. The affected devices are commonly deployed in industrial environments, solar power installations, and remote monitoring systems where maintaining system integrity is paramount. The vulnerability undermines the security posture of these critical infrastructure components and could lead to service disruption, data compromise, or even physical safety risks in environments where these controllers manage power distribution and charging operations.
Mitigation strategies for CVE-2021-34591 should focus on immediate remediation through firmware updates provided by the vendor, which typically address the misconfigured setuid permissions and patch the underlying code vulnerabilities. System administrators should also implement additional security controls such as disabling unnecessary setuid binaries, restricting user access to system resources, and monitoring for suspicious privilege escalation attempts. The vulnerability aligns with CWE-276, which describes improper permissions for critical system resources, and relates to ATT&CK technique T1068, which covers local privilege escalation through exploitation of system vulnerabilities. Organizations should conduct comprehensive security assessments of their embedded systems, review setuid binary configurations, and implement network segmentation to limit the potential impact of such vulnerabilities. Regular security updates and proper access control policies are essential for maintaining the security of industrial control systems and preventing unauthorized elevation of privileges.