CVE-2016-2416 in Android
Summary
by MITRE
libs/gui/BufferQueueConsumer.cpp in mediaserver in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-04-01 does not check for the android.permission.DUMP permission, which allows attackers to obtain sensitive information, and consequently bypass an unspecified protection mechanism, via a dump request, as demonstrated by obtaining Signature or SignatureOrSystem access, aka internal bug 27046057.
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Analysis
by VulDB Data Team • 07/12/2022
The vulnerability described in CVE-2016-2416 represents a critical permission bypass flaw within the Android media server component that affects multiple versions of the operating system. This issue resides in the BufferQueueConsumer.cpp file within the mediaserver process, which serves as a core component responsible for managing graphics buffers and media processing operations. The flaw allows unauthorized attackers to exploit a missing permission check that should have validated the android.permission.DUMP permission before executing sensitive dump operations. This oversight creates a significant security gap that enables malicious actors to access sensitive system information through crafted dump requests.
The technical implementation of this vulnerability stems from the absence of proper permission validation within the mediaserver's buffer queue consumer functionality. When a dump request is made to the mediaserver, the system should verify that the requesting process possesses the appropriate android.permission.DUMP permission before proceeding with the operation. However, the flawed implementation fails to perform this check, allowing any malicious application to submit dump requests and potentially obtain sensitive information about the system's internal state. This permission bypass mechanism specifically enables attackers to gain access to signature-level permissions such as Signature or SignatureOrSystem access, which are typically restricted to system applications and privileged components.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a pathway for attackers to bypass unspecified protection mechanisms within the Android security framework. Attackers can leverage this vulnerability to gather sensitive information about the system's running processes, memory mappings, and potentially access to privileged APIs that should remain restricted. The vulnerability affects a wide range of Android versions including 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before the specified date, indicating a prolonged period of exposure across multiple major releases. This widespread impact suggests that the flaw was not properly addressed in the security updates for these versions, leaving millions of devices vulnerable to exploitation.
The security implications of this vulnerability align with CWE-284, which describes improper access control mechanisms, and represents a clear violation of the principle of least privilege. The ATT&CK framework categorizes this as a privilege escalation technique where an attacker can bypass system protections through information gathering and permission manipulation. The vulnerability demonstrates how seemingly minor missing permission checks can create significant security holes that enable attackers to escalate their privileges and access sensitive system components. Organizations and users affected by this vulnerability should implement immediate mitigations including applying the latest security patches, disabling unnecessary debugging features, and monitoring for suspicious dump requests that could indicate exploitation attempts.
This vulnerability highlights the importance of comprehensive permission validation within system-level components, particularly those that handle sensitive operations and data access. The flaw underscores the need for rigorous security reviews of core system services and the implementation of proper access control mechanisms that validate all incoming requests against appropriate permission sets. The fact that this vulnerability remained unpatched for extended periods in multiple Android versions demonstrates the critical nature of maintaining up-to-date security measures and the potential consequences of inadequate permission validation in core system components.