CVE-2021-1035 in Android
Summary
by MITRE • 01/14/2022
In setLaunchIntent of BluetoothDevicePickerPreferenceController.java, there is a possible way to invoke an arbitrary broadcast receiver due to a confused deputy. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-10 Android-12Android ID: A-195668284
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Analysis
by VulDB Data Team • 01/19/2022
The vulnerability identified as CVE-2021-1035 resides within the BluetoothDevicePickerPreferenceController.java component of Android operating systems ranging from version 10 through 12. This flaw represents a confused deputy problem that occurs during the execution of setLaunchIntent method, where the system fails to properly validate the intent target, potentially allowing malicious actors to manipulate broadcast receiver invocations. The vulnerability stems from insufficient input validation and improper intent handling mechanisms that enable unauthorized components to masquerade as legitimate system services. The affected Android versions encompass a significant portion of devices deployed in enterprise and consumer environments, making this issue particularly concerning for widespread exploitation scenarios.
The technical implementation of this vulnerability involves a scenario where an attacker can construct a malicious intent that appears to originate from a trusted system component but actually redirects execution to an arbitrary broadcast receiver. This occurs because the setLaunchIntent method does not adequately verify the legitimacy of the target component or validate the intent's origin, creating a pathway for privilege escalation. The confused deputy attack pattern, classified under CWE-284, specifically targets situations where a trusted process is tricked into performing actions on behalf of an untrusted entity. The vulnerability manifests when the system's intent resolution mechanism fails to properly authenticate the calling component, allowing unauthorized broadcast receivers to be invoked with elevated privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation as it enables attackers to execute code with system-level privileges without requiring any user interaction or additional malicious payloads. This means that once an attacker successfully exploits the vulnerability, they can potentially access sensitive system resources, modify critical system components, or exfiltrate confidential data without detection. The lack of user interaction requirement makes this vulnerability particularly dangerous for automated exploitation campaigns, as it can be triggered silently during normal device operation. The privilege escalation occurs through the manipulation of Android's component resolution system, where the system incorrectly interprets malicious intents as legitimate system commands, allowing unauthorized code execution with elevated permissions.
Mitigation strategies for CVE-2021-1035 should focus on implementing proper intent validation mechanisms and strengthening component authorization checks within the Android framework. System administrators and device manufacturers should prioritize applying the latest security patches provided by Google, which typically include enhanced intent verification procedures and stricter component validation. The solution involves modifying the BluetoothDevicePickerPreferenceController to implement robust input sanitization and authentication checks before executing any intent resolution. Organizations should also consider implementing application whitelisting policies and monitoring for suspicious broadcast receiver invocations that could indicate exploitation attempts. Additionally, the vulnerability highlights the importance of following secure coding practices and adhering to Android security guidelines that emphasize proper intent handling and component isolation. The ATT&CK framework categorizes this type of vulnerability under privilege escalation techniques, specifically targeting the use of system-level components to gain unauthorized access to protected resources. Regular security audits and penetration testing should include verification of intent handling mechanisms to prevent similar confused deputy scenarios from occurring in other system components.