CVE-2017-9212 in 330i
Summary
by MITRE
The Bluetooth stack on the BMW 330i 2011 allows a remote crash of the CD/Multimedia software via %x or %c format string specifiers in a device name.
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Analysis
by VulDB Data Team • 10/02/2020
The vulnerability identified as CVE-2017-9212 represents a critical format string vulnerability within the Bluetooth stack of BMW 330i vehicles manufactured in 2011. This flaw exists in the CD/Multimedia software component that handles Bluetooth device name parsing, creating a remote code execution vector that could potentially compromise the vehicle's infotainment system. The vulnerability stems from improper input validation when processing device names transmitted over Bluetooth connections, specifically failing to sanitize user-supplied data before using it in format string operations.
The technical implementation of this vulnerability involves the exploitation of standard format string vulnerabilities where maliciously crafted device names containing %x or %c specifiers can trigger undefined behavior in the multimedia software. These format specifiers allow attackers to read memory contents or manipulate the program's execution flow by interpreting stack data as addresses or instructions. The vulnerability operates at the application layer within the Bluetooth protocol implementation, leveraging the inherent trust placed in Bluetooth device connections by the vehicle's infotainment system. This type of vulnerability is classified under CWE-134 as "Use of Externally-Controlled Format String" and aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter.
The operational impact of this vulnerability extends beyond simple system crashes to potentially enabling more sophisticated attacks against vehicle systems. Remote attackers could exploit this vulnerability from outside the vehicle's physical perimeter, leveraging Bluetooth connectivity to deliver malicious payloads that could disrupt vehicle operations, access sensitive data, or potentially interfere with other vehicle systems. The attack surface is particularly concerning given that modern vehicles increasingly rely on connected services and wireless communications for both entertainment and safety-critical functions. The vulnerability demonstrates a fundamental security weakness in automotive software design where insufficient input validation creates opportunities for attackers to manipulate system behavior through seemingly benign user interactions.
Mitigation strategies for CVE-2017-9212 should focus on implementing robust input validation mechanisms within the Bluetooth stack's device name handling routines. Vehicle manufacturers should deploy firmware updates that sanitize all user-supplied data before processing, particularly addressing format string operations by using safe string functions like snprintf instead of sprintf. Network segmentation and Bluetooth access controls should be implemented to limit unauthorized device pairing attempts, while security monitoring systems should be deployed to detect anomalous Bluetooth connection patterns. The vulnerability highlights the importance of applying security patches promptly and maintaining up-to-date vehicle software, as this issue affects a specific model year and could be addressed through targeted firmware updates. Organizations should also consider implementing intrusion detection systems that monitor for suspicious Bluetooth activity and establish secure pairing protocols that validate device authenticity before allowing full system access.