CVE-2016-3884 in Android
Summary
by MITRE
server/notification/NotificationManagerService.java in the Notification Manager Service in Android 6.x before 2016-09-01 and 7.0 before 2016-09-01 lacks uid checks, which allows attackers to bypass intended restrictions on method calls via a crafted application, aka internal bug 29421441.
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Analysis
by VulDB Data Team • 09/15/2022
The vulnerability identified as CVE-2016-3884 resides within the Notification Manager Service component of Android operating systems, specifically affecting versions 6.x and 7.0 prior to the September 1, 2016 security patch release. This flaw represents a critical authorization bypass issue that undermines the security model of the Android notification system. The vulnerability is classified under CWE-284 Access Control Bypass, which occurs when a system fails to properly verify the identity or permissions of entities attempting to access protected resources. The core technical issue manifests in the server/notification/NotificationManagerService.java file where the system fails to perform proper user identifier (uid) validation before processing notification-related method calls.
The operational impact of this vulnerability is significant as it allows malicious applications to execute unauthorized operations within the notification management framework. Attackers can craft specially designed applications that exploit the missing uid checks to bypass intended security restrictions on notification methods. This capability enables unauthorized access to notification services that should only be available to system-level components or applications with appropriate permissions. The vulnerability essentially allows an attacker to manipulate notification behavior, potentially leading to information disclosure, denial of service, or privilege escalation within the Android notification ecosystem. According to ATT&CK framework, this vulnerability maps to T1068 Privilege Escalation and T1546 Persistence, as it provides a mechanism for unauthorized applications to gain elevated privileges and maintain persistent access to notification services.
The technical flaw stems from the absence of proper authentication and authorization checks within the Notification Manager Service implementation. When applications attempt to invoke notification management methods, the system should verify that the calling process possesses the appropriate permissions and user identifiers before executing the requested operations. However, the vulnerable implementation fails to enforce these checks, creating an attack surface where any application can potentially invoke restricted notification methods. This design flaw violates fundamental security principles of least privilege and proper access control enforcement. The vulnerability affects the integrity and confidentiality of the notification system by allowing unauthorized modification of notification behavior, potentially enabling attackers to display misleading notifications, suppress legitimate alerts, or access sensitive notification data that should remain protected. The security implications extend beyond simple notification manipulation to potentially compromise the overall notification ecosystem that serves as a critical communication channel between system services and users.
Mitigation strategies for CVE-2016-3884 focus primarily on applying the relevant security patches released by Google in their September 2016 security updates. Organizations should immediately deploy the Android security patches for versions 6.x and 7.0, ensuring that all devices are updated to versions containing the fixed NotificationManagerService implementation. System administrators should implement comprehensive patch management procedures to verify that all Android devices within their environment have received the necessary updates. Additionally, security monitoring should be enhanced to detect anomalous notification-related activities that might indicate exploitation attempts. The vulnerability highlights the importance of proper access control implementation in system services and underscores the need for rigorous security testing of core Android components. Organizations should also consider implementing application sandboxing and permission monitoring to further reduce the risk of unauthorized notification manipulation, particularly in environments where Android devices are used for sensitive operations or contain confidential information.