CVE-2018-9446 in Android
Summary
by MITRE
In smp_br_state_machine_event of smp_br_main.cc, there is a possible out of bounds write due to memory corruption. This could lead to remote code execution with no additional execution privileges needed. User interaction is not needed for exploitation. Product: Android Versions: Android-6.0 Android-6.0.1 Android-7.0 Android-7.1.1 Android-7.1.2 Android-8.0 Android-8.1 Android ID: A-80145946.
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Analysis
by VulDB Data Team • 06/04/2023
The vulnerability identified as CVE-2018-9446 represents a critical out-of-bounds write flaw within the Bluetooth subsystem of Android operating systems. This issue resides in the smp_br_state_machine_event function located in the smp_br_main.cc source file, which forms part of the Bluetooth stack implementation. The flaw manifests as a memory corruption vulnerability that can be exploited to achieve remote code execution without requiring any additional privileges or user interaction. The vulnerability affects multiple Android versions including 6.0, 6.0.1, 7.0, 7.1.1, 7.1.2, 8.0, and 8.1, indicating a widespread impact across the Android ecosystem. The nature of this vulnerability places it under CWE-787, which specifically addresses out-of-bounds write conditions, making it a serious concern for system security and integrity. The Bluetooth stack component in question handles security management protocol operations, making this vulnerability particularly dangerous as it could be exploited during normal Bluetooth communication scenarios.
The technical exploitation of this vulnerability occurs through a flaw in the state machine implementation that governs Bluetooth security management operations. When the smp_br_state_machine_event function processes incoming Bluetooth security management protocol events, it fails to properly validate array bounds before writing data to memory locations. This memory corruption allows an attacker to overwrite adjacent memory regions, potentially leading to arbitrary code execution. The vulnerability's remote exploitation capability means that an attacker could trigger this flaw through Bluetooth network traffic without requiring physical access or user interaction, aligning with ATT&CK technique T1059.007 for command and scripting interpreter usage. The absence of user interaction requirements makes this vulnerability particularly concerning as it can be exploited passively during normal device operation when Bluetooth is enabled.
The operational impact of CVE-2018-9446 extends beyond simple remote code execution to encompass complete system compromise potential. An attacker who successfully exploits this vulnerability could gain full control over affected Android devices, potentially accessing sensitive user data, installing malicious applications, or using the compromised device as a pivot point for further attacks. The vulnerability's presence in the Bluetooth security management protocol stack means that it could be triggered during routine Bluetooth pairing operations, connection establishment, or security protocol exchanges. This makes the attack surface particularly broad as Bluetooth functionality is commonly enabled on Android devices, and the vulnerability could be exploited during any Bluetooth communication. The lack of privilege requirements means that even devices with minimal security configurations could be compromised, and the no-user-interaction requirement makes this vulnerability particularly dangerous for passive exploitation in public or shared environments.
Mitigation strategies for this vulnerability should focus on immediate patch deployment as provided by Google through Android security updates, which address the underlying memory corruption issue in the Bluetooth stack implementation. Organizations should prioritize updating affected Android devices to versions that contain the patched Bluetooth security management protocol code, particularly those released after the vulnerability disclosure. Network administrators should consider implementing Bluetooth network segmentation and monitoring to detect potential exploitation attempts, as outlined in ATT&CK technique T1046 for network service scanning. Device manufacturers should ensure comprehensive testing of Bluetooth security protocols before deployment, particularly focusing on state machine implementations and memory management practices. Additionally, users should be advised to disable Bluetooth when not actively needed and to keep their devices updated with the latest security patches. The vulnerability's classification under CWE-787 highlights the importance of implementing proper bounds checking and memory validation in security-critical code sections, particularly in protocol handling components that process external input data.