CVE-2018-11909 in Android
Summary
by MITRE
In all android releases(Android for MSM, Firefox OS for MSM, QRD Android) from CAF using the linux kernel, improper access control can lead to device node and executable to be run from /cache/ which presents a potential issue.
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Analysis
by VulDB Data Team • 06/11/2023
The vulnerability identified as CVE-2018-11909 represents a critical access control flaw affecting multiple Android variants including MSM-based devices, Firefox OS for MSM, and QRD Android implementations. This issue stems from the Linux kernel implementation within these mobile platforms and manifests through improper privilege management that allows unauthorized execution of code from the /cache/ filesystem partition. The vulnerability is particularly concerning as it directly impacts the fundamental security model of these operating systems by creating a pathway for malicious code execution through a commonly accessible cache partition. The flaw exists in the kernel-level permission handling mechanisms that govern how device nodes and executable files are accessed and executed within the system.
The technical implementation of this vulnerability exploits weak access control policies that fail to properly validate the source and integrity of executables within the /cache/ directory structure. This partition is typically intended for temporary storage and application caching purposes but lacks sufficient security controls to prevent unauthorized code execution. Attackers can leverage this weakness by placing malicious executables in the cache partition and potentially triggering their execution through various system processes or user interactions. The vulnerability specifically affects systems where the kernel does not properly enforce the principle of least privilege when accessing device nodes and executable files from the cache filesystem, creating a potential attack surface that violates standard security practices.
The operational impact of CVE-2018-11909 extends beyond simple code execution as it fundamentally undermines the security boundaries established by the Android operating system. This vulnerability enables potential attackers to escalate privileges and gain unauthorized access to system resources, potentially leading to complete device compromise. The implications are particularly severe for mobile devices where the cache partition may be writable by multiple system components and user applications. This flaw can be exploited to install persistent backdoors, modify system binaries, or execute arbitrary commands with elevated privileges, making it a critical concern for enterprise security and mobile device management. The vulnerability affects a broad range of devices from various manufacturers who utilize the same kernel implementations, creating widespread exposure across the mobile ecosystem.
Mitigation strategies for this vulnerability should focus on implementing proper kernel-level access controls and strengthening the security boundaries around the /cache/ filesystem partition. System administrators and device manufacturers should ensure that proper file permissions and access controls are enforced for cache directories, preventing unauthorized code execution from these locations. The fix typically involves updating the Linux kernel to a version that properly enforces access control policies for device nodes and executable files within the cache partition. Additionally, implementing runtime monitoring and integrity checking mechanisms can help detect and prevent exploitation attempts. This vulnerability aligns with CWE-284 which addresses improper access control, and could be mapped to ATT&CK techniques involving privilege escalation and persistence through file system manipulation. Organizations should prioritize patching affected systems and implementing additional security controls to prevent exploitation of this access control weakness.