CVE-2019-20601 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with N(7.x), O(8.x), and P(9.0) (Exynos7570, 7580, 7870, 7880, and 8890 chipsets) software. RKP memory corruption causes an arbitrary write to protected memory. The Samsung ID is SVE-2019-13921-2 (May 2019).
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Analysis
by VulDB Data Team • 10/04/2020
This vulnerability represents a critical memory corruption flaw within Samsung's mobile device security architecture affecting devices running Android versions 7.x, 8.x, and 9.0 with specific Exynos chipsets including 7570, 7580, 7870, 7880, and 8890. The vulnerability manifests through the RKP (Runtime Kernel Protection) subsystem which is designed to protect kernel memory from unauthorized access and modifications. The flaw specifically enables an arbitrary write to protected memory regions, creating a severe privilege escalation vector that could allow attackers to bypass critical security protections.
The technical implementation of this vulnerability stems from improper memory management within the RKP subsystem where buffer overflow conditions or improper bounds checking allow malicious code to write data to memory locations that should be protected from modification. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and CWE-125, which addresses out-of-bounds read conditions. The memory corruption occurs at the kernel level where the RKP mechanism fails to properly validate memory access requests, allowing an attacker to manipulate protected kernel memory spaces.
The operational impact of this vulnerability is particularly severe as it enables attackers to achieve kernel-level privileges on affected devices. This arbitrary write capability could be exploited to modify critical system components, install malicious code with root-level access, or bypass security mechanisms such as SELinux policies and kernel address space layout randomization. Attackers could potentially use this vulnerability to establish persistent backdoors, extract sensitive data, or disable security features entirely. The vulnerability affects multiple generations of Samsung devices, creating a widespread attack surface across various smartphone models.
The exploitation of this vulnerability requires sophisticated attack techniques as it involves kernel-level memory manipulation and requires specific conditions to be met for successful exploitation. The RKP subsystem's failure to properly enforce memory protection boundaries creates an attack vector that aligns with ATT&CK technique T1068, which describes the use of local privilege escalation techniques. Security researchers have identified that the vulnerability could be leveraged in conjunction with other exploits to create complete system compromise scenarios. Organizations and users should implement immediate mitigations including firmware updates, device lockdown procedures, and network-based detection measures to prevent exploitation attempts.
Samsung's response to this vulnerability included issuing security patches through their regular update cycle, though the specific timeline and patch availability varied across device models and regions. The vulnerability demonstrates the critical importance of proper memory management in security subsystems and highlights the need for comprehensive testing of kernel-level protections. Device manufacturers must ensure that security features like RKP are properly implemented and validated to prevent similar memory corruption issues from compromising system integrity. This vulnerability serves as a reminder of the complex security challenges inherent in mobile device ecosystems where hardware and software security features must work in concert to provide adequate protection against sophisticated attack vectors.