CVE-2019-9474 in Android
Summary
by MITRE
In Bluetooth, there is a possible out of bounds read due to a missing bounds check. This could lead to remote information disclosure with no additional execution privileges needed. User interaction is not needed for exploitation. Product: Android Versions: Android-10 Android ID: A-79996267
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Analysis
by VulDB Data Team • 03/16/2020
The vulnerability identified as CVE-2019-9474 represents a critical out-of-bounds read flaw within the Bluetooth implementation of Android 10 systems. This issue stems from a fundamental missing bounds check in the Bluetooth stack that processes incoming data packets. The flaw exists at the kernel level within the Bluetooth subsystem where insufficient validation occurs when handling malformed Bluetooth packets, particularly those containing crafted payload data that exceeds expected buffer boundaries. Such missing validation creates an exploitable condition where an attacker can craft specific Bluetooth packets that trigger memory access violations, leading to potential information disclosure from adjacent memory regions.
The technical nature of this vulnerability aligns with CWE-129, which describes improper validation of array indices, and CWE-131, which covers incorrect calculation of buffer size. The flaw operates at the boundary between user-space Bluetooth libraries and kernel-space Bluetooth protocol handling, where insufficient input sanitization allows memory corruption that can be leveraged for information disclosure. This type of vulnerability falls under the ATT&CK technique T1059.007 for Command and Scripting Interpreter: PowerShell, though more accurately represents a memory corruption primitive that can be used to extract sensitive data from system memory. The vulnerability demonstrates a classic buffer over-read condition where the Bluetooth stack attempts to access memory beyond the allocated buffer boundaries without proper bounds checking mechanisms.
The operational impact of CVE-2019-9474 is significant as it enables remote information disclosure without requiring any user interaction or additional privileges beyond basic Bluetooth connectivity. An attacker positioned within Bluetooth range of an affected Android 10 device can exploit this vulnerability by transmitting specially crafted Bluetooth packets that trigger the out-of-bounds read condition. The information disclosure aspect means that sensitive data from adjacent memory locations could be exposed, potentially including cryptographic keys, session tokens, or other confidential information stored in memory. This vulnerability represents a serious threat to privacy and security as it can be exploited remotely over the air without user awareness, making it particularly dangerous in environments where Bluetooth connectivity is enabled.
Mitigation strategies for CVE-2019-9474 should focus on both immediate patching and operational security measures. Android users should apply the relevant security patches released by Google as part of the Android security bulletin for September 2019, which specifically address this Bluetooth vulnerability. Organizations should also implement Bluetooth network segmentation and monitoring to detect anomalous Bluetooth traffic patterns that might indicate exploitation attempts. Network administrators should consider disabling Bluetooth functionality on devices where it is not essential, particularly in high-security environments. Additionally, implementing Bluetooth packet filtering rules and monitoring for malformed Bluetooth traffic can help detect potential exploitation attempts. The vulnerability highlights the importance of robust input validation and bounds checking in kernel-level code, emphasizing that security-by-design principles must be applied throughout all system components, particularly those handling network protocols and wireless communications.