CVE-2018-9322 in BMW
Summary
by MITRE
The Head Unit HU_NBT (aka Infotainment) component on BMW i Series, BMW X Series, BMW 3 Series, BMW 5 Series, and BMW 7 Series vehicles produced in 2012 through 2018 allows local attacks involving the USB or OBD-II interface. An attacker can bypass the code-signing protection mechanism for firmware updates, and consequently obtain a root shell.
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Analysis
by VulDB Data Team • 02/10/2020
The vulnerability identified as CVE-2018-9322 represents a critical security flaw within the infotainment systems of BMW vehicles spanning multiple model lines from 2012 to 2018. This weakness resides in the Head Unit HU_NBT component, which serves as the primary interface for vehicle entertainment and connectivity functions. The vulnerability specifically targets the code-signing protection mechanisms designed to ensure firmware integrity and prevent unauthorized modifications to the vehicle's infotainment system. The attack surface is particularly concerning as it leverages legitimate vehicle interfaces including USB ports and OBD-II connections, which are commonly accessible to vehicle owners and service technicians. This design flaw creates an attack vector that bypasses fundamental security controls intended to maintain system integrity and protect against malicious firmware modifications.
The technical implementation of this vulnerability stems from inadequate validation of firmware update authenticity within the vehicle's infotainment system. Attackers can exploit this weakness through physical access to the vehicle's USB or OBD-II interfaces to inject malicious firmware updates that circumvent the code-signing verification process. The successful exploitation results in privilege escalation to root level access, effectively granting attackers complete control over the vehicle's infotainment system. This root shell access enables adversaries to execute arbitrary code, modify system configurations, access sensitive data, and potentially interface with other vehicle control systems. The vulnerability demonstrates a failure in implementing proper cryptographic validation mechanisms and demonstrates a clear violation of security principles that should prevent unauthorized modifications to critical vehicle systems.
The operational impact of CVE-2018-9322 extends beyond simple infotainment system compromise to potentially threaten vehicle safety and privacy. With root access to the infotainment system, attackers could potentially gain access to vehicle diagnostic information, communication protocols, and other sensitive data that could be exploited for vehicle tracking, data theft, or even control system manipulation. The vulnerability affects multiple BMW model series including the i Series, X Series, 3 Series, 5 Series, and 7 Series, indicating a widespread exposure across BMW's vehicle portfolio. This vulnerability aligns with CWE-311, which describes the absence of encryption or the use of weak encryption for sensitive data, and more specifically relates to CWE-276, which addresses improper privileges for security-critical operations. The attack methodology also corresponds to ATT&CK technique T1059, which involves executing commands through legitimate system interfaces.
Mitigation strategies for this vulnerability should include immediate firmware updates from BMW to address the code-signing bypass mechanism, along with enhanced physical security measures to prevent unauthorized access to vehicle interfaces. Vehicle owners should be advised to avoid connecting untrusted USB devices and to exercise caution when using OBD-II interfaces for diagnostics. Security monitoring systems should be implemented to detect unauthorized firmware modifications or unusual system behavior. Additionally, the vulnerability highlights the importance of implementing secure boot mechanisms and robust cryptographic validation processes in automotive systems, as recommended by automotive cybersecurity standards such as ISO/SAE 21434 and the automotive security framework established by the Auto Industry Security Committee. Organizations should also consider implementing network segmentation and intrusion detection systems to monitor for suspicious activities that could indicate exploitation attempts.