CVE-2019-20594 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with O(8.1) and P(9.0) (Exynos chipsets) software. A heap overflow exists in the bootloader. The Samsung ID is SVE-2019-14371 (July 2019).
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Analysis
by VulDB Data Team • 10/04/2020
The vulnerability identified as CVE-2019-20594 represents a critical heap overflow condition within the bootloader component of Samsung mobile devices equipped with Exynos chipsets running Android 8.1 Oreo and 9.0 Pie operating system versions. This issue manifests at the lowest level of the device's software stack, specifically within the bootloader phase that initializes the device's operating system. The heap overflow vulnerability occurs during the early boot process when the bootloader handles memory allocation and management, creating a potential attack surface that could be exploited before the device reaches its normal operational state. The Samsung internal tracking identifier SVE-2019-14371 confirms this was recognized and documented by Samsung's security team in July 2019, indicating the severity and urgency of the issue.
The technical flaw stems from improper memory boundary checks within the bootloader's heap management routines. When processing specific input data or commands during the boot sequence, the bootloader fails to validate the size of memory allocations, allowing an attacker to write beyond the allocated heap buffer boundaries. This heap overflow condition creates opportunities for arbitrary code execution within the bootloader environment, which operates with elevated privileges and access to critical system components. The vulnerability is particularly concerning because it exists in the pre-boot environment where traditional security mitigations such as address space layout randomization and stack canaries may not be fully operational, making exploitation more straightforward and reliable.
The operational impact of this vulnerability extends beyond simple device compromise, as it provides attackers with access to the device's most fundamental boot processes. An attacker who successfully exploits this heap overflow could potentially install malicious firmware, modify boot parameters, or gain persistent access to the device before the operating system loads. This represents a significant threat to device integrity and user privacy, as the attack vector operates below the normal operating system layer where most security controls are implemented. The vulnerability affects a substantial number of Samsung devices, particularly those using Exynos chipsets, which were widely deployed across various smartphone models during the 2018-2019 timeframe, creating a broad potential attack surface.
Mitigation strategies for this vulnerability primarily focus on firmware updates and patches provided by Samsung, which address the heap overflow condition through proper memory boundary validation and heap management improvements. Organizations and users should prioritize applying the official security patches released by Samsung to remediate this vulnerability. Additionally, security researchers and device manufacturers should implement enhanced bootloader integrity checks and runtime monitoring to detect anomalous memory allocation patterns. The vulnerability aligns with CWE-122 (Heap Overflow) and represents a significant concern within the ATT&CK framework under the T1059.001 (Command and Scripting Interpreter) and T1068 (Exploitation for Privilege Escalation) techniques, as it enables attackers to achieve elevated privileges through boot-level exploitation. Network security teams should monitor for exploitation attempts targeting this specific vulnerability and consider implementing device firmware integrity checking mechanisms to detect unauthorized modifications to the bootloader components.