CVE-2020-0473 in Android
Summary
by MITRE • 12/15/2020
In updateIncomingFileConfirmNotification of BluetoothOppNotification.java, there is a possible permissions bypass. This could lead to local escalation of privilege allowing an attacker with physical possession of the device to transfer files to it over Bluetooth, with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-160691486
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Analysis
by VulDB Data Team • 12/18/2020
The vulnerability identified as CVE-2020-0473 resides within the Bluetooth OPP (Object Push Profile) notification handling component of Android operating systems, specifically affecting Android 11 and earlier versions. This flaw exists in the updateIncomingFileConfirmNotification method of the BluetoothOppNotification.java file, which governs how incoming Bluetooth file transfer notifications are processed. The vulnerability represents a critical security weakness that undermines the system's permission model and could potentially allow unauthorized file transfers to occur without proper authentication or authorization mechanisms.
The technical flaw manifests as a permissions bypass that occurs during the processing of incoming Bluetooth file notifications. When a device receives a Bluetooth file transfer request, the system should validate the source and ensure appropriate permissions are granted before allowing the transfer to proceed. However, this vulnerability allows an attacker with physical possession of the device to circumvent these security checks, enabling them to transfer files over Bluetooth without requiring any additional execution privileges or user interaction. The flaw essentially removes the necessary permission verification steps that should occur during the notification confirmation process, creating an attack vector that can be exploited through physical access alone.
From an operational impact perspective, this vulnerability creates a significant risk for Android devices that are physically accessible to unauthorized individuals. The local escalation of privilege aspect means that an attacker who gains physical possession of a device can perform file transfers without needing to establish additional execution privileges or bypass other security controls. This could potentially allow for the installation of malicious software, data exfiltration, or the deployment of persistent backdoors. The vulnerability is particularly concerning because it requires no user interaction for exploitation, making it a passive attack vector that can be activated simply by placing a device within Bluetooth range of an attacker.
The implications of this vulnerability align with CWE-284, which addresses improper access control, and can be categorized under ATT&CK technique T1059.001 for command and scripting interpreter, as it may enable an attacker to establish malicious file transfers that could subsequently be executed on the device. The vulnerability essentially creates a backdoor mechanism through which attackers can introduce unauthorized content into the device's file system without triggering the normal security checks that would typically prevent such transfers.
Mitigation strategies should focus on implementing proper permission validation mechanisms within the Bluetooth OPP notification handling code, ensuring that all file transfer requests undergo rigorous authentication and authorization checks before any data is processed. System updates should enforce stricter access controls for Bluetooth file transfers, requiring explicit user confirmation or device authentication before allowing file operations to proceed. Organizations should also consider implementing device encryption and physical security measures to prevent unauthorized access, while mobile device management solutions should be configured to monitor and restrict Bluetooth file transfer capabilities. Additionally, users should be educated about the risks of leaving Bluetooth enabled in untrusted environments, and regular security updates should be applied to ensure the vulnerability is patched in the affected Android versions.