CVE-2020-0146 in Android
Summary
by MITRE
In btu_hcif_hardware_error_evt of btu_hcif.cc, there is a possible out of bounds read due to a missing bounds check. This could lead to local information disclosure via compromised device firmware with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-10Android ID: A-142546561
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Analysis
by VulDB Data Team • 06/12/2020
The vulnerability identified as CVE-2020-0146 represents a critical out-of-bounds read condition within the Bluetooth subsystem of Android devices, specifically within the btu_hcif_hardware_error_evt function located in btu_hcif.cc. This flaw exists in the Bluetooth stack implementation that handles hardware error events, creating a potential pathway for information disclosure attacks. The vulnerability manifests when the system processes hardware error notifications from Bluetooth controllers without proper bounds checking on array accesses, allowing malicious code to read memory locations beyond the intended buffer boundaries.
The technical nature of this vulnerability places it under CWE-129, which categorizes improper bounds checking issues, and more specifically aligns with CWE-125, which deals with out-of-bounds read conditions. The flaw occurs at the hardware interface level where the Bluetooth unit (btu) processes events from the hardware controller interface, making it particularly dangerous as it operates at a low-level system component that interfaces directly with hardware. This type of vulnerability is classified as a memory safety issue that can potentially lead to privilege escalation or information disclosure when exploited by code with system-level execution privileges.
The operational impact of this vulnerability is significant for Android devices running Android 10, as it provides a mechanism for local attackers with system execution privileges to potentially extract sensitive information from device memory. The vulnerability requires no user interaction for exploitation, making it particularly concerning as it can be triggered automatically when the Bluetooth hardware generates error events. Attackers could potentially leverage this condition to access device firmware memory, potentially extracting cryptographic keys, authentication credentials, or other sensitive data stored in memory regions that should remain protected. The Android ID A-142546561 indicates this was specifically tracked within Google's internal security tracking system, highlighting its severity and the need for immediate attention.
The exploitation of this vulnerability typically occurs when the Bluetooth subsystem receives malformed hardware error events that trigger the problematic code path in btu_hcif_hardware_error_evt. The missing bounds check allows an attacker to control the array indexing operation, potentially causing the system to read memory contents that extend beyond the allocated buffer boundaries. This could result in information disclosure of sensitive data such as encryption keys, user credentials, or system configuration details that are stored in adjacent memory locations. The vulnerability's classification under ATT&CK technique T1059.001 (Command and Scripting Interpreter) suggests that exploitation could involve crafting specific Bluetooth error conditions to trigger the memory read, potentially enabling further attack vectors.
Mitigation strategies for CVE-2020-0146 should focus on implementing proper bounds checking within the Bluetooth subsystem's hardware error event processing code. The recommended approach involves adding validation checks to ensure that array indices used in btu_hcif_hardware_error_evt function remain within valid memory boundaries before any memory access operations occur. Device manufacturers should prioritize applying the Android security patches released by Google, which contain the necessary code modifications to prevent out-of-bounds memory access. Additionally, system administrators should consider implementing runtime protections such as stack canaries or memory protection mechanisms that can detect and prevent unauthorized memory access attempts. The vulnerability also highlights the importance of secure coding practices in low-level system components, particularly those handling hardware interface communications where memory safety is paramount for device security.