CVE-2021-0504 in Android
Summary
by MITRE • 06/21/2021
In avrc_pars_browse_rsp of avrc_pars_ct.cc, there is a possible out of bounds read due to a missing bounds check. This could lead to remote information disclosure over Bluetooth with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-179162665
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Analysis
by VulDB Data Team • 06/24/2021
The vulnerability identified as CVE-2021-0504 resides within the Android Bluetooth implementation, specifically in the AVRCP (Audio Video Remote Control Profile) parsing functionality. This issue manifests in the avrc_pars_browse_rsp function located in the avrc_pars_ct.cc source file, representing a critical security flaw that could enable remote information disclosure through Bluetooth connections. The vulnerability stems from an inadequate bounds checking mechanism that fails to validate input data length before processing, creating a potential attack vector for malicious actors to extract sensitive information from affected Android devices.
The technical flaw constitutes a classic out-of-bounds read condition that falls under the CWE-129 vulnerability category, specifically addressing improper validation of array indices or object bounds. This type of vulnerability occurs when the system attempts to access memory locations beyond the allocated buffer boundaries without proper validation, potentially exposing adjacent memory contents to unauthorized access. The AVRCP profile is commonly used for controlling media playback on Bluetooth devices, making this vulnerability particularly concerning as it operates within the core Bluetooth media control functionality. The absence of bounds checking in the parsing logic means that malformed or specially crafted Bluetooth packets can trigger memory access violations that may leak confidential information.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables remote exploitation without requiring any additional privileges or user interaction. This characteristic places the vulnerability in the ATT&CK matrix under the T1059.001 technique category, specifically targeting remote service access and exploitation through network protocols. The fact that no user interaction is required for exploitation makes this vulnerability particularly dangerous as it can be triggered automatically when a device attempts to process Bluetooth browsing responses from malicious sources. Affected Android 11 devices with the identified Android ID A-179162665 are vulnerable to this attack vector, potentially exposing sensitive data through Bluetooth connections that are typically considered secure.
Mitigation strategies for this vulnerability should focus on implementing proper bounds checking mechanisms within the Bluetooth AVRCP parsing functions, ensuring that all input data is validated before processing. The recommended approach involves adding comprehensive validation routines that verify the length and structure of incoming Bluetooth packets before attempting to parse them, thereby preventing the out-of-bounds memory access. Additionally, Android security updates and patches should be deployed immediately to address this vulnerability, as the affected implementation requires modification to the core Bluetooth stack components. System administrators and device manufacturers should prioritize this patch deployment to protect against potential exploitation by threat actors who may attempt to leverage this vulnerability for information gathering or further attacks within Bluetooth-enabled networks.