CVE-2019-2009 in Android
Summary
by MITRE
In l2c_lcc_proc_pdu of l2c_fcr.cc, there is a possible out of bounds write due to a missing bounds check. This could lead to remote code execution over Bluetooth with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-7.0 Android-7.1.1 Android-7.1.2 Android-8.0 Android-8.1 Android-9Android ID: A-120665616
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Analysis
by VulDB Data Team • 10/07/2023
The vulnerability identified as CVE-2019-2009 represents a critical out-of-bounds write flaw within the Bluetooth stack of Android operating systems, specifically affecting versions ranging from 7.0 through 9.0. This issue resides in the l2c_lcc_proc_pdu function located in the l2c_fcr.cc source file, which forms part of the Logical Link Control and Adaptation Protocol (L2CAP) implementation. The vulnerability stems from the absence of proper bounds checking mechanisms when processing incoming Bluetooth protocol data units, creating a scenario where maliciously crafted Bluetooth packets could trigger memory corruption. The flaw operates at the transport layer of the Bluetooth protocol stack, specifically within the flow control and retransmission mechanisms that govern how data is transmitted between Bluetooth devices.
The technical nature of this vulnerability places it under CWE-787, which specifically addresses out-of-bounds write conditions where an attacker can write data beyond the boundaries of a allocated buffer. This type of vulnerability is particularly dangerous because it can lead to arbitrary code execution without requiring any additional privileges or user interaction, making it highly attractive to threat actors. The Bluetooth protocol operates at the link layer and above, and this particular flaw affects the L2CAP layer which handles segmentation and reassembly of data packets. The absence of bounds checking in the pdu processing function means that when the system receives malformed data packets, it fails to validate the size or content limits before writing to memory locations, potentially allowing attackers to overwrite adjacent memory regions.
The operational impact of CVE-2019-2009 extends beyond simple data corruption, as it provides a pathway for remote code execution through Bluetooth communication channels. This vulnerability affects all supported Android versions, creating a widespread exposure across millions of devices that rely on Bluetooth connectivity for various services including wireless headphones, smartwatches, fitness trackers, and automotive systems. The exploitability is particularly concerning because it does not require user interaction, meaning devices can be compromised simply by being within range of an attacker's malicious Bluetooth device. The attack surface is broad given that Bluetooth is enabled by default on most Android devices and many applications utilize Bluetooth for background connectivity. This vulnerability aligns with ATT&CK technique T1059.006 for remote code execution through network protocols, and represents a significant threat to device integrity and user privacy.
Mitigation strategies for CVE-2019-2009 should focus on immediate patching of affected Android versions, with the most effective solution being the installation of security updates from Google that address the bounds checking deficiency in the L2CAP implementation. Organizations should implement Bluetooth security policies that disable unnecessary Bluetooth services and restrict Bluetooth connectivity to trusted devices only. Network administrators should consider deploying Bluetooth monitoring tools to detect anomalous Bluetooth traffic patterns that might indicate exploitation attempts. Device manufacturers should ensure that Bluetooth stack implementations include robust input validation and bounds checking mechanisms. The vulnerability also highlights the importance of secure coding practices in embedded systems and mobile platforms, particularly in protocol implementations that handle untrusted network data. Additionally, users should be advised to keep their Android devices updated and to avoid connecting to untrusted Bluetooth devices, especially in public environments where such attacks could be more easily executed.