CVE-2022-20257 in Android
Summary
by MITRE • 08/12/2022
In Bluetooth, there is a possible way to pair a display only device without PIN confirmation due to a logic error in the code. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-13Android ID: A-222289114
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Analysis
by VulDB Data Team • 09/11/2022
This vulnerability resides within the Bluetooth pairing mechanism of Android 13 systems, specifically affecting the display-only device pairing process. The issue stems from a fundamental logic error in the Bluetooth stack implementation that allows unauthorized pairing when the display-only device should require PIN confirmation. The flaw operates at the protocol level where the system fails to properly validate the pairing sequence, creating a bypass condition that undermines the security model designed to prevent unauthorized device connections. This represents a critical weakness in the authentication framework that governs Bluetooth device interactions.
The technical execution of this vulnerability exploits a race condition or state validation flaw within the Bluetooth pairing protocol implementation. When a display-only device attempts to pair with another device, the system should enforce PIN confirmation as a mandatory security measure. However, due to the logic error, the pairing process can proceed without this verification step, effectively allowing an attacker to establish a connection without proper authentication. This condition exists at the kernel level Bluetooth stack where the pairing state machine does not properly enforce the required confirmation sequence. The vulnerability demonstrates a failure in the Bluetooth security protocol implementation that aligns with CWE-284 access control weaknesses and represents a classic example of improper privilege management in security-critical systems.
The operational impact of this vulnerability extends to potential local privilege escalation scenarios where an attacker could gain elevated system privileges without requiring additional execution privileges or user interaction. This means that an attacker could potentially establish unauthorized Bluetooth connections and leverage this access to perform actions that would normally require higher privileges. The implications are particularly severe because the attack requires no user interaction, making it a passive threat that can be exploited automatically. This vulnerability essentially provides a backdoor into the system's Bluetooth security framework, potentially allowing for data exfiltration, device control, or further exploitation of other system components. The lack of user interaction requirement makes this particularly dangerous in environments where Bluetooth devices are frequently paired or where the system operates in unattended modes.
Mitigation strategies for this vulnerability should focus on immediate system updates and patches provided by Google and device manufacturers to address the Bluetooth stack logic error. Organizations should implement Bluetooth device whitelisting policies and disable unnecessary Bluetooth pairing functionality where possible. Security monitoring should be enhanced to detect unauthorized Bluetooth pairing attempts and establish baseline behaviors for legitimate device connections. The patch implementation should address the core logic error in the Bluetooth pairing state machine and ensure proper validation of PIN confirmation requirements. Additionally, system administrators should conduct thorough security assessments of Bluetooth-enabled devices and consider implementing network segmentation to limit potential attack vectors. This vulnerability highlights the importance of proper access control implementation and demonstrates how flaws in authentication protocols can lead to privilege escalation without requiring additional attack vectors or user interaction.