CVE-2019-2020 in Android
Summary
by MITRE
In llcp_dlc_proc_rr_rnr_pdu of llcp_dlc.cc, there is a possible out-of-bound read due to a missing bounds check. This could lead to local information disclosure with no additional execution privileges needed. User interaction needed for exploitation.Product: AndroidVersions: Android-7.0 Android-7.1.1 Android-7.1.2 Android-8.0 Android-8.1 Android-9Android ID: A-116788646
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Analysis
by VulDB Data Team • 10/07/2023
The vulnerability identified as CVE-2019-2020 resides within the Bluetooth Low Energy (BLE) implementation of Android operating systems, specifically in the Logical Link Control and Adaptation Protocol (LLCP) layer. This issue manifests in the llcp_dlc_proc_rr_rnr_pdu function located in the llcp_dlc.cc source file, representing a critical security flaw that affects multiple Android versions including 7.0, 7.1.1, 7.1.2, 8.0, 8.1, and 9. The vulnerability stems from a missing bounds check during processing of specific BLE protocol data units, creating a potential out-of-bounds read condition that could be exploited to extract sensitive information from system memory.
The technical flaw represents a classic buffer over-read vulnerability that falls under CWE-129, which describes improper validation of the length or index of a buffer. When the LLCP component processes certain received data units, it fails to validate the boundaries of memory access operations, allowing an attacker to potentially read data from adjacent memory locations. This particular implementation flaw occurs during the handling of Remote Ready/Remote Not Ready PDU messages, which are part of the BLE connection management protocol. The missing bounds check means that the system does not verify whether the data being processed fits within the allocated memory boundaries before accessing it, creating an exploitable condition that can lead to information disclosure.
The operational impact of this vulnerability is significant despite requiring user interaction for exploitation, as it enables local information disclosure without the need for additional execution privileges. An attacker could potentially leverage this vulnerability to extract sensitive data such as cryptographic keys, session information, or other confidential data stored in adjacent memory locations. The attack vector typically requires the user to interact with a malicious Bluetooth device or application that can trigger the vulnerable code path, making it particularly concerning for mobile environments where Bluetooth interactions are common. This vulnerability aligns with ATT&CK technique T1059.001, which covers command and scripting interpreter, as the exploitation could potentially lead to further system compromise through information gathering.
The mitigation strategies for this vulnerability involve applying the security patches released by Google as part of their regular Android security updates. Organizations should prioritize updating affected Android devices to versions that contain the fix for this specific LLCP implementation flaw. Additionally, system administrators should monitor for any signs of exploitation attempts and consider implementing network monitoring to detect unusual Bluetooth traffic patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation and bounds checking in network protocol implementations, as highlighted by industry standards and best practices for secure coding. Regular security assessments of Bluetooth implementations and other network protocols should include thorough review of memory access patterns and validation mechanisms to prevent similar vulnerabilities from being introduced in future releases.