CVE-2016-3930 in Android
Summary
by MITRE
The NVIDIA MMC test driver in Android before 2016-10-05 on Nexus 9 devices allows attackers to gain privileges via a crafted application, aka internal bug 28760138.
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Analysis
by VulDB Data Team • 05/01/2019
The vulnerability identified as CVE-2016-3930 represents a critical privilege escalation flaw within the NVIDIA MultiMedia Card (MMC) test driver component of Android operating systems. This vulnerability specifically affected Nexus 9 devices running Android versions prior to the October 5, 2016 security update, creating a persistent security weakness that could be exploited by malicious applications to elevate their privileges from standard user level to system-level access. The flaw was classified as an internal bug with the identifier 28760138, indicating its discovery within NVIDIA's internal development and testing processes. The vulnerability stems from improper input validation and privilege handling within the MMC test driver, which is responsible for managing multimedia card operations in Android devices. This particular driver component was designed for testing purposes but remained accessible to regular applications, creating an unintended attack surface that adversaries could leverage.
The technical implementation of this vulnerability involves a flaw in how the MMC test driver processes certain input parameters and handles privilege checks during device operations. Attackers could craft malicious applications that exploit buffer overflows, integer overflows, or improper access control mechanisms within the driver code to manipulate memory structures and bypass normal security boundaries. The vulnerability enables attackers to execute arbitrary code with kernel-level privileges, effectively granting them complete control over the device's operating system and all its resources. This type of flaw typically falls under CWE-119, which addresses "Improper Access to Memory Location" and specifically relates to buffer overflows or memory corruption issues that can lead to privilege escalation. The attack vector requires only a malicious application to be installed and executed on the target device, making it particularly dangerous as it can be delivered through normal application distribution channels without requiring physical access or specialized equipment.
The operational impact of CVE-2016-3930 extends far beyond simple privilege escalation, as it provides attackers with comprehensive system control capabilities that could lead to complete device compromise. Once exploited, the vulnerability allows unauthorized access to all device data including personal information, credentials, and communication records, while also enabling persistent backdoor access that could survive device reboots. The vulnerability affects devices running Android versions that were widely distributed and used in enterprise and consumer environments, creating a significant risk for organizations relying on these devices. Security researchers have mapped this vulnerability to ATT&CK technique T1068, which covers "Local Privilege Escalation" and specifically addresses the exploitation of kernel-level vulnerabilities to gain administrative access. The impact is particularly severe given that Nexus 9 devices were popular among enterprise users and developers, making the potential attack surface extensive and the exploitation risk high.
Mitigation strategies for CVE-2016-3930 primarily focus on applying the security patches released by Google and NVIDIA in their October 2016 updates, which addressed the underlying driver implementation flaws. Organizations should immediately deploy the Android security updates to all affected devices, particularly those running Android versions prior to 6.0.1. The patch typically involves strengthening input validation within the MMC test driver, implementing proper privilege checks, and ensuring that test driver components are properly isolated from user-space applications. System administrators should also consider implementing application whitelisting policies that prevent installation of untrusted applications, as this vulnerability can be exploited through legitimate application channels. Additionally, monitoring for suspicious application behavior and implementing device integrity checks can help detect potential exploitation attempts. The vulnerability serves as a reminder of the importance of proper driver security implementation and the need for continuous security testing of kernel-level components, particularly those designed for testing purposes but remaining accessible in production environments. Organizations should also review their mobile device management policies to ensure comprehensive protection against similar vulnerabilities in other system components.