CVE-2019-1992 in Android
Summary
by MITRE
In bta_hl_sdp_query_results of bta_hl_main.cc, there is a possible use-after-free due to a race condition. This could lead to remote code execution with no additional execution privileges needed. User interaction is needed for exploitation. Product: Android. Versions: Android-7.0 Android-7.1.1 Android-7.1.2 Android-8.0 Android-8.1 Android-9. Android ID: A-116222069.
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Analysis
by VulDB Data Team • 07/26/2023
The vulnerability identified as CVE-2019-1992 represents a critical use-after-free condition within the Bluetooth Health (HL) profile implementation of Android's Bluetooth subsystem. This flaw exists in the bta_hl_sdp_query_results function located in the bta_hl_main.cc source file, where a race condition allows for improper memory management during Bluetooth service discovery processes. The vulnerability specifically affects Android versions from 7.0 through 9.0, making it a widespread issue across multiple Android releases. The root cause stems from inadequate synchronization mechanisms that permit concurrent access to shared memory resources during Bluetooth service discovery operations, creating a window where freed memory can be accessed by subsequent operations.
The technical exploitation of this vulnerability requires a specific sequence of events involving Bluetooth service discovery and concurrent access patterns that trigger the race condition. When a malicious Bluetooth device initiates service discovery and simultaneously triggers memory deallocation operations, the system may attempt to access previously freed memory locations. This use-after-free condition can be leveraged to execute arbitrary code with the privileges of the Bluetooth subsystem, which typically runs with system-level permissions. The vulnerability's remote code execution capability means that an attacker does not require local access or additional privileges to exploit the flaw, as it can be triggered through Bluetooth network interactions. The requirement for user interaction suggests that the attack vector likely involves the user accepting a Bluetooth connection request or service discovery prompt, which then triggers the vulnerable code path.
From an operational perspective, this vulnerability poses significant security risks to Android devices as it enables attackers to gain remote code execution capabilities through Bluetooth interactions without requiring physical access or user credentials. The impact extends beyond simple privilege escalation as the Bluetooth subsystem typically has access to sensitive device functions and data. The vulnerability's classification aligns with CWE-416 which describes use-after-free conditions, and its exploitation pattern matches techniques documented in the MITRE ATT&CK framework under the T1059.007 sub-technique for command and scripting interpreter. The race condition aspect of this vulnerability also relates to broader security concepts in software development where concurrency issues can lead to memory corruption vulnerabilities. The fact that this affects multiple Android versions indicates a fundamental flaw in the Bluetooth implementation that was not properly addressed across the affected release cycle.
Mitigation strategies for CVE-2019-1992 primarily involve applying the security patches released by Google as part of their regular Android security updates. Organizations should prioritize immediate deployment of the relevant security patches that address the race condition in the Bluetooth Health profile implementation. System administrators should disable Bluetooth functionality when not required and implement strict Bluetooth device pairing policies to minimize exposure windows. Network monitoring solutions should be configured to detect anomalous Bluetooth service discovery patterns that might indicate exploitation attempts. The vulnerability highlights the importance of proper memory management in concurrent programming environments and reinforces the need for comprehensive testing of race condition scenarios in mobile operating systems. Additionally, device manufacturers should consider implementing additional runtime protections such as address space layout randomization and stack canaries to make exploitation more difficult even if the underlying vulnerability remains unpatched.