CVE-2019-20572 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with O(8.1) and P(9.0) (Exynos chipsets) software. load_kernel has a buffer overflow via untrusted data. The Samsung ID is SVE-2019-14939 (September 2019).
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Analysis
by VulDB Data Team • 10/04/2020
This vulnerability resides within the kernel loading mechanism of Samsung mobile devices equipped with Exynos chipsets running Android 8.1 and 9.0 operating system versions. The issue manifests as a buffer overflow condition that occurs when the load_kernel component processes untrusted input data from external sources. This flaw represents a critical security weakness that could potentially allow malicious actors to execute arbitrary code within the kernel space of affected devices. The vulnerability was identified and tracked under Samsung's internal tracking system as SVE-2019-14939, highlighting its significance within Samsung's security assessment framework. The buffer overflow vulnerability specifically affects the kernel loading process, which is a fundamental component responsible for initializing the operating system kernel during device boot operations.
The technical exploitation of this vulnerability occurs through the manipulation of untrusted data that flows into the load_kernel function without proper bounds checking. When the system attempts to load kernel modules or components, it fails to validate the size and content of incoming data, creating a condition where an attacker can overflow the allocated buffer space. This buffer overflow can potentially overwrite adjacent memory locations, including function return addresses or critical control variables, enabling attackers to redirect execution flow. The vulnerability falls under the CWE-121 buffer overflow category, which is classified as a critical weakness in memory safety. The attack surface is particularly concerning because it operates at the kernel level, where successful exploitation could lead to complete system compromise and persistent root access.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete system takeover capabilities for adversaries. Once exploited, attackers could gain unrestricted access to the device's core operating system functions, potentially enabling them to install malicious applications, modify system files, access sensitive user data, or establish persistent backdoors. The vulnerability affects a significant number of Samsung devices that utilize Exynos chipsets, creating a wide attack surface across multiple device models and generations. This type of kernel-level vulnerability aligns with ATT&CK technique T1068 which describes "Exploitation for Privilege Escalation" and represents a critical threat vector for mobile device security. The impact is particularly severe because it operates below the application layer, making detection and prevention significantly more challenging for traditional mobile security solutions.
Mitigation strategies for this vulnerability should focus on immediate software updates provided by Samsung through their security patches and firmware updates. Users should promptly install all available security updates for their devices, as these patches typically include memory boundary checks and input validation improvements to prevent the buffer overflow condition. Device manufacturers and security teams should implement comprehensive monitoring for exploitation attempts and establish robust input sanitization protocols for kernel loading components. The vulnerability also underscores the importance of secure coding practices and thorough code review processes for kernel-level components, particularly those handling external data inputs. Organizations should consider implementing mobile device management solutions that can automatically enforce security updates and monitor for suspicious behavior patterns that might indicate exploitation attempts. Additionally, regular security assessments of kernel components and adherence to secure development lifecycle practices can help prevent similar vulnerabilities from emerging in future software releases.