CVE-2016-2475 in Android
Summary
by MITRE
The Broadcom Wi-Fi driver in Android before 2016-06-01 on Nexus 5, Nexus 6, Nexus 6P, Nexus 7 (2013), Nexus 9, Nexus Player, and Pixel C devices allows attackers to gain privileges for certain system calls via a crafted application, aka internal bug 26425765.
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Analysis
by VulDB Data Team • 01/18/2019
The vulnerability identified as CVE-2016-2475 represents a critical privilege escalation flaw within the Broadcom Wi-Fi driver component of Android operating systems. This security weakness affected numerous flagship devices including the Nexus 5, Nexus 6, Nexus 6P, Nexus 7 (2013), Nexus 9, Nexus Player, and Pixel C models. The vulnerability stems from improper validation of system calls within the Wi-Fi driver implementation, creating an exploitable path for malicious applications to elevate their privileges beyond normal user restrictions. The flaw specifically manifested in the driver's handling of certain system calls that should have been restricted to privileged processes only, allowing unprivileged applications to execute these operations with elevated privileges.
The technical implementation of this vulnerability involves a flaw in the kernel-level Wi-Fi driver that fails to properly validate input parameters when processing specific system calls. When a crafted application attempts to invoke these system calls through the Wi-Fi driver interface, the driver does not adequately verify the caller's privileges or the legitimacy of the requested operations. This validation failure creates a direct path for privilege escalation, enabling malicious applications to execute code with system-level privileges. The vulnerability operates at the kernel level within the Android security model, bypassing standard user-space privilege controls and directly exploiting the trust relationship between the application and the underlying driver component. According to CWE classification, this represents a privilege escalation vulnerability (CWE-269) that allows unauthorized access to system resources through improper access control mechanisms.
The operational impact of CVE-2016-2475 extends beyond simple privilege escalation, as it fundamentally undermines the security boundaries within the Android operating system. Attackers who successfully exploit this vulnerability can gain complete control over affected devices, potentially accessing sensitive user data, modifying system configurations, installing malicious applications, or even disabling security features. The affected devices represent a significant portion of the Android ecosystem from that time period, making the vulnerability particularly dangerous as it could affect millions of users. The exploitation requires only a malicious application that can be distributed through normal app channels, making the attack surface extremely broad and difficult to prevent. This vulnerability directly impacts the Android security model's principle of least privilege and can be categorized under ATT&CK technique T1068 for privilege escalation through kernel exploits.
Mitigation strategies for CVE-2016-2475 primarily involve applying the security patches released by Google and device manufacturers as part of the Android security updates. Users should immediately install all available system updates for their affected devices to remediate this vulnerability. Device manufacturers should ensure that their update distribution mechanisms are functioning properly to deliver these patches to users promptly. Network administrators should monitor their device inventories to identify affected systems and prioritize patching efforts, particularly in enterprise environments where these devices may be in use. The vulnerability demonstrates the critical importance of maintaining up-to-date device firmware and security patches, as the flaw existed in the system driver layer where traditional mobile security controls may not be sufficient to prevent exploitation. Additionally, users should exercise caution when installing applications from untrusted sources and maintain awareness of the security implications of granting applications access to system resources, as the vulnerability specifically leverages the trust relationship between legitimate applications and the kernel driver components.