CVE-2018-9312 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 a local attack when a USB device is plugged in.
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Analysis
by VulDB Data Team • 02/10/2020
The vulnerability identified as CVE-2018-9312 affects the Head Unit HU_NBT component in BMW vehicles spanning multiple series including i Series, X Series, 3 Series, 5 Series, and 7 Series from model years 2012 through 2018. This represents a significant security weakness in automotive infotainment systems that enables local attack vectors through physical USB device connections. The flaw resides within the vehicle's infotainment system architecture where it fails to properly validate or sanitize input from connected USB devices, creating an exploitable entry point for malicious actors who gain physical access to the vehicle's USB ports.
The technical implementation of this vulnerability stems from inadequate input validation mechanisms within the HU_NBT component's USB handling routines. When a USB device is connected to the vehicle's infotainment system, the system does not perform proper authentication or security checks on the device before establishing communication channels. This weakness allows for potential code execution or system manipulation through malicious USB devices that can exploit the trust relationship between the vehicle's infotainment system and connected peripherals. The vulnerability aligns with CWE-20, which describes improper input validation, and represents a clear violation of secure coding practices in automotive embedded systems. The attack surface is particularly concerning because it requires minimal physical access to the vehicle and can be executed through simple USB device insertion.
From an operational perspective, this vulnerability presents a substantial risk to vehicle security and data integrity. Attackers with physical access to the vehicle can potentially execute arbitrary code on the infotainment system, potentially gaining access to vehicle control functions or sensitive data stored within the system. The impact extends beyond simple infotainment disruption to encompass potential compromise of vehicle safety systems, as the infotainment system often shares network buses with critical vehicle functions. This vulnerability also enables potential data exfiltration from the vehicle's internal systems, creating risks for personal information stored on connected devices or transmitted through vehicle networks. The attack vector's accessibility through simple USB insertion means that even unskilled attackers can potentially exploit this weakness, making it particularly dangerous in real-world scenarios where physical access to vehicles is common.
Mitigation strategies for CVE-2018-9312 should focus on both immediate operational responses and long-term architectural improvements. Vehicle owners and fleet managers should consider disabling USB ports when not in use or implementing physical security measures to prevent unauthorized device insertion. BMW should provide firmware updates to address the input validation deficiencies in the HU_NBT component, though this requires careful consideration of vehicle safety systems and potential compatibility issues. The vulnerability demonstrates the importance of implementing secure boot processes and runtime integrity checks for automotive infotainment systems, aligning with automotive security standards such as ISO 21448 (SOTIF) and ISO 26262 for functional safety. Organizations should also consider network segmentation approaches that isolate infotainment systems from critical vehicle control networks to prevent lateral movement of attacks. This vulnerability highlights the necessity of applying the principle of least privilege in automotive systems and implementing proper device authentication mechanisms before granting system access to connected peripherals. The incident underscores the growing need for automotive cybersecurity frameworks that address both physical and network-based attack vectors in modern connected vehicles.