CVE-2016-3845 in Android
Summary
by MITRE
The video driver in the kernel in Android before 2016-08-05 on Nexus 5 devices allows attackers to gain privileges via a crafted application, aka internal bug 28399876.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 03/20/2019
The vulnerability identified as CVE-2016-3845 represents a critical privilege escalation flaw within the Android kernel's video driver component affecting Nexus 5 devices prior to the 2016-08-05 security patch release. This vulnerability operates at the kernel level, exploiting weaknesses in how the system handles video driver operations that allow malicious applications to execute code with elevated privileges. The flaw specifically targets the Android operating system's kernel implementation where video driver functionality is managed, creating an attack vector that bypasses normal security boundaries between user-space applications and the privileged kernel space. The vulnerability's designation as an internal bug 28399876 indicates it was recognized and tracked by Google's internal security teams before public disclosure, highlighting the severity and complexity of the underlying issue. The attack requires a crafted malicious application that can leverage the video driver's improper privilege handling to escalate from standard user-level permissions to kernel-level privileges.
The technical implementation of this vulnerability stems from inadequate input validation and privilege management within the kernel's video driver subsystem. When a malicious application attempts to interact with video driver functions through the appropriate system calls, the kernel fails to properly validate the application's privileges or properly enforce access controls during video processing operations. This allows the attacker to manipulate memory structures or execute code sequences that should only be accessible to the kernel itself. The vulnerability operates under CWE-264, which classifies it as a permissions, privileges, and access controls weakness, specifically manifesting as an improper privilege management scenario where kernel-level resources are accessible through user-space applications. The attack vector involves exploiting the video driver's interface to perform operations that would normally require kernel privileges, effectively creating a path for privilege escalation through the kernel's graphics processing subsystem.
The operational impact of CVE-2016-3845 extends beyond simple privilege escalation, as it provides attackers with complete control over the affected device's kernel space. Once successfully exploited, the malicious application can execute arbitrary code with the highest system privileges, enabling full system compromise including access to sensitive data, modification of system files, installation of persistent backdoors, and complete control over device functionality. This vulnerability particularly affects Nexus 5 devices running Android versions prior to the August 2016 security update, making them susceptible to sophisticated attacks that could compromise user privacy, device integrity, and overall system security. The impact is significant because it allows attackers to bypass all standard Android security mechanisms including SELinux policies, application sandboxing, and other privilege separation controls that normally protect against unauthorized access to system resources. This vulnerability also aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation', and represents a classic example of how kernel-level vulnerabilities can be leveraged for complete system compromise.
Mitigation strategies for CVE-2016-3845 focus primarily on applying the vendor-provided security patches released in the 2016-08-05 Android security update, which addressed the underlying privilege escalation flaw in the video driver implementation. Device administrators should immediately deploy the latest security updates to ensure all affected Nexus 5 devices receive the necessary kernel-level fixes. Additionally, organizations should implement application whitelisting policies to prevent installation of untrusted applications that could exploit this vulnerability, as well as monitor for suspicious application behavior that might indicate exploitation attempts. The vulnerability's resolution demonstrates the importance of maintaining up-to-date security patches and highlights the critical nature of kernel-level security controls in mobile operating systems. Security professionals should also consider implementing network-based monitoring to detect potential exploitation attempts and establish incident response procedures specifically tailored to handle kernel-level privilege escalation attacks. The remediation process requires careful verification that the security patches have been properly applied and that no malicious applications remain on the device, as the vulnerability could enable persistent backdoor installation that might survive system reboots.