CVE-2019-20578 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with P(9.0) (Exynos 9820 chipsets) software. A Buffer overflow occurs when loading the UH Partition during Secure Boot. The Samsung ID is SVE-2019-14412 (August 2019).
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 10/04/2020
This vulnerability represents a critical buffer overflow condition within the secure boot process of Samsung devices running Android 9.0 with Exynos 9820 chipsets. The flaw manifests specifically during the loading of the UH Partition, which serves as a crucial component in the device's trusted execution environment. The buffer overflow occurs at the kernel level during the boot sequence, potentially allowing malicious actors to compromise the device's security foundation before the operating system fully initializes. This vulnerability directly impacts the integrity of the secure boot chain and represents a significant threat to device authenticity and data protection.
The technical implementation of this vulnerability stems from inadequate input validation during the UH Partition loading process. When the secure boot mechanism attempts to process partition data, insufficient bounds checking allows an attacker to provide malicious input that exceeds the allocated buffer space. This condition enables arbitrary code execution within the privileged boot environment, potentially allowing attackers to bypass security measures and gain root access to the device. The vulnerability is particularly concerning because it occurs during the earliest stages of device boot, before standard security mitigations can be effectively applied. The flaw aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of how improper memory management can compromise system security during critical initialization phases.
The operational impact of this vulnerability extends beyond simple device compromise, as it provides attackers with a pathway to establish persistent footholds within Samsung devices. Successful exploitation could enable attackers to install rootkits, modify system binaries, or extract sensitive cryptographic keys stored in the device's secure element. The vulnerability affects all Samsung devices with Exynos 9820 chipsets running Android 9.0, representing a substantial attack surface across multiple device models including flagship smartphones and tablets. From an adversarial perspective, this vulnerability maps to ATT&CK technique T1068, which describes the use of local privilege escalation to gain root access, and T1542, which covers exploitation of system services for privilege escalation. The attack vector likely involves supplying malformed partition data through compromised firmware updates or physical access to the device.
Mitigation strategies for this vulnerability require immediate firmware updates from Samsung, as the flaw resides in hardware-level boot components that cannot be patched through standard operating system updates. Organizations should implement device management policies that enforce immediate security patches upon release, while also monitoring for suspicious boot behavior that might indicate exploitation attempts. Network security teams should be aware that compromised devices may exhibit unusual network traffic patterns or attempt to communicate with command and control servers. The vulnerability highlights the importance of hardware-based security measures and proper input validation in trusted execution environments. Security professionals should also consider implementing device integrity monitoring solutions that can detect unauthorized modifications to boot components. Given the nature of the vulnerability, device manufacturers should consider implementing additional runtime checks and memory protection mechanisms to prevent similar issues in future hardware designs.