CVE-2020-0309 in Android
Summary
by MITRE
In the Bluetooth server, there is a possible out of bounds write due to an integer overflow. This could lead to local escalation of privilege with System privileges and a Firmware compromise needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-147227320
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Analysis
by VulDB Data Team • 09/19/2020
The vulnerability identified as CVE-2020-0309 represents a critical security flaw within Android's Bluetooth server implementation that manifests as an out-of-bounds write condition stemming from an integer overflow. This issue exists within the Android operating system version 11 and is tracked under Android ID A-147227320. The flaw specifically affects the Bluetooth subsystem's handling of certain data structures where integer overflow conditions can occur during memory allocation calculations, potentially leading to memory corruption scenarios that compromise system integrity.
The technical root cause of this vulnerability lies in improper input validation and arithmetic overflow handling within the Bluetooth server component responsible for processing incoming Bluetooth packets and managing Bluetooth-related operations. When the system processes specific Bluetooth protocol data units or configuration parameters, integer overflow conditions can occur during calculations involving buffer sizes or memory allocation parameters. This overflow results in a situation where the calculated buffer size exceeds the intended boundaries, leading to memory corruption that manifests as an out-of-bounds write operation. The vulnerability is particularly concerning because it can be exploited to achieve local privilege escalation to system-level privileges, bypassing standard security boundaries that normally protect the Android operating system from unauthorized access.
The operational impact of CVE-2020-0309 extends beyond simple data corruption, as it enables potential firmware-level compromise and complete system takeover. An attacker who successfully exploits this vulnerability can escalate privileges from a standard user context to system-level privileges, effectively gaining control over the entire device. This level of access allows for complete modification of system firmware, installation of malicious software, and unauthorized access to all device data. The requirement for firmware compromise indicates that the vulnerability can be leveraged to modify core system components that are typically protected from modification, making it particularly dangerous for mobile device security. The lack of user interaction requirements for exploitation means that the vulnerability can be triggered automatically during normal Bluetooth operations, increasing the attack surface and making it more difficult to defend against.
From a cybersecurity perspective, this vulnerability aligns with CWE-190, which addresses integer overflow and underflow conditions, and demonstrates characteristics consistent with ATT&CK technique T1068, which involves exploiting local privilege escalation vulnerabilities. The vulnerability's classification as a local privilege escalation issue means it fits within the ATT&CK framework's privilege escalation category and can be used as a stepping stone for more comprehensive attacks. The fact that it requires firmware compromise suggests potential integration with techniques involving rootkit development or system-level malware deployment. Security practitioners should consider this vulnerability as part of a broader attack chain that could lead to complete device compromise, particularly in environments where Bluetooth connectivity is frequently used or where devices may be physically accessible to adversaries.
Mitigation strategies for CVE-2020-0309 should focus on immediate patch deployment through official Android security updates, which would address the integer overflow conditions in the Bluetooth server implementation. Organizations should also implement network-level controls to limit unnecessary Bluetooth connectivity and disable Bluetooth when not actively needed. System administrators should monitor for unusual Bluetooth activity patterns that might indicate exploitation attempts and consider implementing additional security controls such as Bluetooth access restrictions or device profiling to prevent automatic exploitation. The vulnerability's nature as a local privilege escalation issue also warrants attention to overall device security posture, including secure boot mechanisms and firmware integrity verification processes to prevent exploitation attempts from succeeding even if other security measures fail.