CVE-2022-20140 in Android
Summary
by MITRE • 06/15/2022
In read_multi_rsp of gatt_sr.cc, there is a possible out of bounds write due to an incorrect bounds check. This could lead to remote escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-12 Android-12LAndroid ID: A-227618988
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Analysis
by VulDB Data Team • 06/15/2022
The vulnerability identified as CVE-2022-20140 resides within the Bluetooth GATT (Generic Attribute Profile) implementation of Android 12 and 12L operating systems. This flaw exists in the read_multi_rsp function located in the gatt_sr.cc source file, which is part of the Bluetooth stack responsible for handling GATT server operations. The issue manifests as an out-of-bounds write condition that occurs due to an insufficient bounds check during the processing of multiple read responses from Bluetooth GATT clients. This particular implementation flaw represents a critical security weakness that allows for privilege escalation without requiring any additional execution privileges or user interaction for exploitation.
The technical nature of this vulnerability stems from improper input validation within the Bluetooth GATT server component where the system fails to adequately verify array boundaries when processing multiple read responses. When a malicious Bluetooth device or application sends specially crafted GATT read requests, the system's response handling mechanism can write data beyond the allocated memory buffer, potentially overwriting adjacent memory regions. This memory corruption vulnerability operates at the kernel level within the Bluetooth subsystem and can be exploited remotely through Bluetooth connections without requiring any user interaction or additional privileges. The flaw specifically targets the gatt_sr.cc file's read_multi_rsp function, which handles multiple read responses in a GATT server context and demonstrates a classic buffer overflow condition.
The operational impact of this vulnerability is severe as it enables remote privilege escalation, allowing an attacker to gain elevated system privileges without requiring local access or user interaction. This means that an attacker positioned within Bluetooth range could potentially exploit this vulnerability to execute arbitrary code with system-level privileges, effectively compromising the entire Android device. The attack vector is particularly concerning because it leverages the Bluetooth protocol, which is widely enabled on mobile devices and often operates in background modes, making exploitation more likely and harder to detect. The vulnerability affects all Android 12 and 12L devices, representing a significant security risk across a large user base. According to CWE classification, this vulnerability maps to CWE-787 Out-of-bounds Write, which is categorized under the broader weakness of improper bounds checking in memory management.
From an attack framework perspective, this vulnerability aligns with ATT&CK technique T1068, which involves the exploitation of legitimate credentials or system access to gain elevated privileges. The remote exploitation capability makes this particularly dangerous as it can be triggered through standard Bluetooth communication without requiring any specialized tools or physical access to the device. The lack of user interaction requirement means that exploitation can occur passively, making it an ideal target for automated attacks or malicious actors who wish to compromise devices while they are in normal operation. Organizations should consider this vulnerability as a critical threat requiring immediate attention, especially in environments where Bluetooth connectivity is frequently used or where device security is paramount. The vulnerability's classification under the Android security advisory A-227618988 indicates that it has been formally recognized and addressed by Google's security team, but devices that have not received the relevant security patches remain at risk. The exploitability of this vulnerability makes it a prime target for advanced persistent threat actors who seek to establish persistent access to mobile devices through remote attack vectors.