CVE-2016-3849 in Android
Summary
by MITRE
The ION driver in Android before 2016-08-05 on Pixel C devices allows attackers to gain privileges via a crafted application, aka internal bug 28939740.
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Analysis
by VulDB Data Team • 03/20/2019
The vulnerability identified as CVE-2016-3849 represents a critical privilege escalation flaw within the ION driver component of Android operating systems, specifically affecting devices including the Pixel C released prior to the security patch cycle of August 2016. This vulnerability resides in the kernel-level memory management subsystem that handles buffer allocation and deallocation for graphics and multimedia processing operations. The ION driver serves as a memory allocator for the Android system, managing shared memory buffers between various system components and applications. When exploited, this flaw allows malicious applications to elevate their privileges from standard user-level processes to kernel-level operations, effectively bypassing the operating system's security model and gaining complete control over the device's resources.
The technical exploitation of this vulnerability stems from improper input validation and memory management practices within the ION driver implementation. Attackers can craft malicious applications that manipulate the driver's memory allocation functions to trigger buffer overflows or use-after-free conditions, which subsequently lead to arbitrary code execution in kernel space. The vulnerability specifically targets the driver's handling of memory mapping operations and buffer management structures, allowing attackers to manipulate kernel memory pointers and overwrite critical system data structures. This type of flaw typically falls under the CWE-121 category of stack-based buffer overflow or CWE-787 for out-of-bounds write conditions, both of which are classified as high-severity issues in the Common Weakness Enumeration catalog. The attack vector requires local execution privileges, meaning that an attacker must first install a malicious application on the target device, though once executed, the exploit can achieve complete system compromise.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally undermines the security architecture of Android devices by allowing attackers to bypass the kernel-level protections that normally isolate user applications from critical system resources. Once an attacker achieves kernel-level access through this vulnerability, they can modify system files, install persistent backdoors, extract sensitive data, and manipulate device functionality without detection. The vulnerability particularly affects devices running Android versions prior to the August 2016 security patch, making it a significant concern for users who had not yet applied the necessary updates. From an adversary perspective, this vulnerability aligns with ATT&CK technique T1068, which involves exploiting legitimate credentials or system privileges to gain access to restricted resources, and T1059, which encompasses executing malicious code through application interfaces. The exploitation of such vulnerabilities often forms part of broader attack campaigns targeting mobile devices, as the compromised devices can serve as entry points for network infiltration or as platforms for further malicious activities.
Mitigation strategies for CVE-2016-3849 primarily focus on applying the relevant security patches released by Google and device manufacturers, which address the underlying memory management flaws in the ION driver. Users should ensure their devices receive all available security updates, particularly those released in the August 2016 cycle, which included fixes for this specific vulnerability. Device administrators should implement strict application vetting processes and avoid installing untrusted applications from unknown sources. Network security teams should monitor for indicators of compromise related to this vulnerability, including unusual kernel-level processes or unauthorized access attempts. Additionally, organizations should consider implementing mobile device management solutions that can enforce security policies and automatically apply security patches to managed devices. The vulnerability serves as a reminder of the critical importance of timely security updates and proper kernel memory management practices in mobile operating systems, highlighting the need for continuous security monitoring and proactive vulnerability remediation strategies.