CVE-2019-9257 in Android
Summary
by MITRE
In Bluetooth, there is a possible out of bounds write due to an integer overflow. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Product: AndroidVersions: Android-10Android ID: A-113572342
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 09/12/2020
The vulnerability identified as CVE-2019-9257 represents a critical security flaw within the Bluetooth implementation of Android 10 operating systems. This issue manifests as an out-of-bounds write condition that arises from an integer overflow within the Bluetooth subsystem. The vulnerability exists in the kernel-level Bluetooth stack where insufficient input validation and boundary checking allow for malicious data processing that can exceed allocated memory boundaries. The flaw specifically impacts the Android 10 operating system and has been assigned the Android ID A-113572342, indicating its severity and the need for immediate attention.
The technical root cause of this vulnerability stems from improper handling of integer values during Bluetooth protocol processing. When the Bluetooth subsystem receives certain malformed or specially crafted data packets, it fails to properly validate the size parameters before performing memory allocation operations. This integer overflow condition allows an attacker to manipulate memory layout and potentially overwrite adjacent memory locations. The vulnerability is classified under CWE-129 as an "Improper Validation of Array Index" and can be categorized under ATT&CK technique T1068 for "Exploitation for Privilege Escalation." The integer overflow occurs during the processing of Bluetooth service discovery or connection establishment protocols where size calculations are performed without adequate overflow protection mechanisms.
The operational impact of this vulnerability is significant as it enables local privilege escalation without requiring any additional execution privileges or user interaction. An attacker with local access to an Android 10 device can exploit this flaw to gain elevated privileges within the system, potentially allowing them to execute arbitrary code with system-level permissions. The lack of user interaction requirement makes this vulnerability particularly dangerous as it can be exploited automatically without the victim's knowledge or consent. This type of vulnerability undermines the fundamental security model of Android systems by allowing unauthorized code execution within the kernel space, which could result in complete system compromise, data theft, or persistent backdoor installation.
Mitigation strategies for CVE-2019-9257 should focus on immediate patch deployment from Google as part of the Android security updates. Organizations and users must ensure their Android 10 devices receive the latest security patches that address the integer overflow condition in Bluetooth protocol handling. System administrators should implement network monitoring to detect anomalous Bluetooth traffic patterns that might indicate exploitation attempts. Additionally, device hardening measures such as disabling unnecessary Bluetooth functionality when not in use and implementing proper access controls can reduce the attack surface. The vulnerability highlights the importance of robust input validation and memory safety practices in kernel-level code development, aligning with industry standards that emphasize proper boundary checking and integer overflow prevention techniques. Security teams should also consider implementing behavioral monitoring solutions that can detect unusual privilege escalation patterns that might indicate exploitation of this vulnerability.