CVE-2018-9555 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 escalation of privilege over Bluetooth with no additional execution privileges needed. User interaction is not needed for exploitation. Product: Android. Versions: Android-7.0 Android-7.1.1 Android-7.1.2 Android-8.0 Android-8.1 Android-9. Android ID: A-112321180.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 04/18/2020
The vulnerability identified as CVE-2018-9555 represents a critical out-of-bounds write flaw within the Bluetooth stack implementation of Android operating systems. 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) layer responsible for managing Bluetooth connections. The flaw stems from the absence of proper bounds checking mechanisms when processing incoming Bluetooth protocol data units, creating a potential avenue for arbitrary code execution. The vulnerability affects multiple Android versions including 7.0, 7.1.1, 7.1.2, 8.0, 8.1, and 9.0, indicating a widespread impact across the Android ecosystem. This type of vulnerability falls under CWE-787, which specifically addresses out-of-bounds write conditions that can lead to memory corruption and privilege escalation. The attack vector is particularly concerning because it enables remote exploitation without requiring any user interaction or additional execution privileges, making it highly dangerous in practical scenarios.
The technical implementation of this vulnerability occurs during the processing of Bluetooth protocol data units where the system fails to validate the size or boundaries of incoming data before writing to memory locations. When a malicious Bluetooth device or network transmits specially crafted L2CAP packets, the l2c_lcc_proc_pdu function attempts to write data beyond the allocated memory buffer, potentially overwriting adjacent memory regions. This memory corruption can be leveraged to execute arbitrary code with the privileges of the Bluetooth stack process, which typically runs with elevated system permissions. The absence of user interaction requirements makes this vulnerability particularly dangerous as it can be exploited through passive Bluetooth scanning or active network-based attacks. The flaw represents a classic example of improper input validation and memory management, which aligns with ATT&CK technique T1068 for local privilege escalation and T1566 for credential access through network-based attacks.
The operational impact of CVE-2018-9555 extends beyond simple privilege escalation, as it fundamentally compromises the security boundary of Bluetooth communications within Android devices. An attacker could potentially gain complete control over affected devices, enabling them to install malicious applications, access sensitive data, modify system configurations, or establish persistent backdoors. The vulnerability's remote exploitability means that attackers do not need physical access to devices or proximity to target systems, as Bluetooth networks can be compromised from greater distances. This creates a significant risk for enterprise environments where Bluetooth devices are commonly used for various applications including IoT deployments, mobile payments, and wireless peripherals. The lack of user interaction requirements also makes this vulnerability particularly difficult to detect and defend against, as it can be exploited silently in the background. Organizations relying on Android devices for sensitive operations must consider this vulnerability as a critical threat requiring immediate attention and remediation.
Mitigation strategies for CVE-2018-9555 should prioritize immediate patching of affected Android versions through official security updates from Google and device manufacturers. System administrators should implement network-based monitoring to detect anomalous Bluetooth traffic patterns that could indicate exploitation attempts. The recommended approach includes disabling unnecessary Bluetooth functionality when not in use, implementing Bluetooth device whitelisting policies, and deploying network segmentation to limit potential attack surfaces. Organizations should also consider implementing mobile device management solutions that can enforce security policies and automatically apply security patches. Additionally, regular security assessments should include Bluetooth protocol analysis to identify potential exploitation vectors. The vulnerability demonstrates the importance of robust input validation and memory safety practices in system-level code, particularly in network protocol implementations that handle untrusted data from external sources. Security teams should also monitor for related vulnerabilities in similar Bluetooth stack implementations across different platforms and ensure comprehensive testing of security controls before deploying updates to production environments.