CVE-2018-5889 in Android
Summary
by MITRE
While processing a compressed kernel image, a buffer overflow can occur in Android releases from CAF using the linux kernel (Android for MSM, Firefox OS for MSM, QRD Android) before security patch level 2018-06-05.
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Analysis
by VulDB Data Team • 04/05/2023
The vulnerability identified as CVE-2018-5889 represents a critical buffer overflow condition that manifests during the processing of compressed kernel images within Android systems. This flaw affects multiple Android variants including those based on the Linux kernel for MSM platforms, Firefox OS for MSM, and QRD Android implementations. The vulnerability exists in devices that utilize code from the Code Aurora Forum (CAF) and becomes exploitable when the system attempts to decompress kernel images during the boot process or system initialization. The buffer overflow occurs in kernel space, making it particularly dangerous as it can potentially allow privilege escalation and system compromise. This vulnerability specifically impacts devices running Android versions that incorporate CAF kernel code and affects systems before the security patch level of June 5, 2018.
The technical implementation of this vulnerability stems from insufficient bounds checking during decompression operations of kernel images. When the system processes compressed kernel data, the decompression routine fails to properly validate the size of input data against allocated buffer boundaries. This allows an attacker to craft malicious compressed kernel images that, when processed by the vulnerable system, can overwrite adjacent memory locations in the kernel's memory space. The flaw is classified under CWE-121 as a stack-based buffer overflow, though it may also manifest as heap-based overflow depending on the specific decompression implementation. The vulnerability operates at the kernel level where memory management and system integrity are paramount, making any exploitation potentially catastrophic for system security and stability.
The operational impact of CVE-2018-5889 extends beyond simple system crashes or denial of service conditions. An attacker who can successfully exploit this vulnerability gains the ability to execute arbitrary code with kernel-level privileges, effectively compromising the entire system. This capability aligns with ATT&CK technique T1068 which describes the use of local privilege escalation to gain system-level access. The vulnerability's exploitation can lead to complete system compromise, allowing attackers to install persistent backdoors, extract sensitive data, modify system files, or establish covert communication channels. Given that this affects mobile devices running Android and related platforms, the exploitation could enable access to personal data, communications, and potentially corporate networks through compromised mobile devices. The vulnerability is particularly concerning because it can be triggered during normal system boot operations, making exploitation possible without requiring user interaction or specialized attack vectors.
Mitigation strategies for CVE-2018-5889 primarily focus on applying the relevant security patches released by device manufacturers and the Android security team. Organizations should prioritize updating all affected devices to security patch level 2018-06-05 or later, which contains the necessary fixes for the buffer overflow condition. The patch typically involves implementing proper bounds checking in the kernel decompression routines and ensuring that input data sizes are validated against allocated buffer capacities. Additionally, system administrators should consider implementing additional security controls such as kernel module signing enforcement, secure boot mechanisms, and monitoring for suspicious decompression activities. From a defensive perspective, this vulnerability highlights the importance of kernel security hardening practices and regular security assessments of embedded systems. Network administrators should also monitor for potential exploitation attempts through anomalous boot process patterns or unexpected kernel memory behaviors. The vulnerability underscores the necessity of maintaining up-to-date security patches across all system components, particularly those handling compressed data or kernel-level operations, as recommended in industry best practices for embedded system security.