CVE-2020-8539 in Head Unit
Summary
by MITRE • 12/01/2020
Kia Motors Head Unit with Software version: SOP.003.30.18.0703, SOP.005.7.181019, and SOP.007.1.191209 may allow an attacker to inject unauthorized commands, by executing the micomd executable deamon, to trigger unintended functionalities. In addition, this executable may be used by an attacker to inject commands to generate CAN frames that are sent into the M-CAN bus (Multimedia CAN bus) of the vehicle.
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Analysis
by VulDB Data Team • 12/11/2020
The vulnerability identified as CVE-2020-8539 affects Kia Motors head unit systems operating with specific software versions including SOP.003.30.18.0703, SOP.005.7.181019, and SOP.007.1.191209. This represents a critical security flaw in automotive infotainment systems that could enable remote command injection attacks. The vulnerability stems from the micomd executable daemon which serves as an entry point for unauthorized command execution within the vehicle's infotainment architecture. This daemon operates with elevated privileges and provides access to core vehicle communication protocols that should remain protected from external manipulation.
The technical implementation of this vulnerability involves the exploitation of the micomd daemon to inject unauthorized commands that can trigger unintended functionalities within the vehicle's system. This daemon acts as a bridge between the infotainment interface and the vehicle's internal communication networks, specifically the M-CAN bus which handles multimedia and entertainment system communications. The flaw allows attackers to bypass normal security controls and execute arbitrary code through this privileged process. According to CWE-78, this represents a command injection vulnerability where attacker-supplied commands are executed as part of a software system, while the ATT&CK framework categorizes this under T1059.007 for command and script injection targeting the vehicle's operating system level.
The operational impact of this vulnerability extends beyond simple command injection to include the ability to generate CAN frames that are transmitted over the M-CAN bus, potentially affecting vehicle safety systems. This capability allows attackers to manipulate vehicle communication protocols and could enable them to access other vehicle systems that share the same CAN network. The vulnerability creates a pathway for attackers to potentially disrupt vehicle operations, access sensitive data, or even compromise vehicle safety systems that depend on the CAN bus for communication. The exposure of the micomd daemon to unauthorized command execution represents a fundamental breakdown in automotive cybersecurity defenses.
Mitigation strategies for CVE-2020-8539 should focus on immediate software updates and patch management to address the vulnerable micomd daemon implementation. Vehicle manufacturers must implement proper privilege separation and access controls for system daemons to prevent unauthorized command execution. Network segmentation of vehicle CAN buses should be considered to limit the impact of potential attacks. Security monitoring systems should be deployed to detect anomalous command execution patterns and unauthorized CAN frame generation. The vulnerability highlights the need for automotive security standards such as ISO/SAE 21434 and SOTIF (Safety of the Intended Functionality) compliance, which require systematic approaches to identifying and mitigating cybersecurity risks in vehicle systems. Additionally, implementing secure boot processes and runtime application control mechanisms would help prevent execution of unauthorized code through the micomd daemon.