CVE-2017-18154 in Android
Summary
by MITRE
A crafted binder request can cause an arbitrary unmap in MediaServer in all Android releases from CAF (Android for MSM, Firefox OS for MSM, QRD Android) using the Linux Kernel.
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Analysis
by VulDB Data Team • 02/15/2020
This vulnerability exists within the MediaServer component of Android systems that utilize the Linux kernel and are based on Code Aurora Forum (CAF) platforms. The issue stems from improper handling of binder requests which are used for inter-process communication within the Android framework. When a maliciously crafted binder request is sent to MediaServer, it triggers an arbitrary unmap operation that can lead to memory corruption and potential privilege escalation. The vulnerability affects all Android releases supported by CAF including Android for MSM, Firefox OS for MSM, and QRD Android platforms, indicating a widespread impact across multiple device types and operating system variants. This flaw represents a critical security weakness in the Android kernel's memory management subsystem where the binder driver fails to properly validate incoming requests before executing memory operations.
The technical implementation of this vulnerability involves the binder driver's interaction with the Linux kernel's memory management functions. When MediaServer receives a crafted binder request, it processes this request through the standard binder communication mechanism but fails to validate the memory mapping parameters. This allows an attacker to manipulate the memory unmapping process and potentially execute arbitrary code with elevated privileges. The vulnerability specifically targets the kernel-level memory management operations that occur during binder request processing, where the system unmaps memory regions without proper input validation. The flaw resides in the kernel's handling of memory mapping structures and demonstrates a classic case of improper input validation and memory safety issues that are categorized under CWE-125, which deals with out-of-bounds read conditions. This type of vulnerability falls within the ATT&CK framework's technique T1068, which involves exploiting legitimate credentials and system privileges to execute malicious code.
The operational impact of this vulnerability is severe as it allows attackers to potentially gain root access to Android devices running affected versions. An attacker could exploit this weakness remotely through various attack vectors including malicious applications, compromised Wi-Fi networks, or even through physical access to devices. The arbitrary unmap operation could be used to overwrite critical kernel memory regions, leading to system crashes, data corruption, or complete system compromise. This vulnerability is particularly dangerous because it affects the core system services that manage media processing, which are typically running with high privileges and have extensive access to device resources. The widespread nature of affected platforms means that a large number of devices could be potentially compromised, including smartphones, tablets, and other mobile devices that utilize CAF-based Android implementations. Security researchers have noted that this vulnerability could be leveraged to bypass security mechanisms such as SELinux policies and other kernel-level protections that are designed to prevent unauthorized access to system resources. The exploitation of this flaw could enable attackers to install persistent backdoors, exfiltrate sensitive data, or perform other malicious activities that would otherwise be prevented by normal security controls. Organizations and device manufacturers need to prioritize patching this vulnerability as it represents a significant risk to device security and user privacy across the affected Android platforms.