CVE-2019-20558 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with N(7.x), O(8.x), and P(9.0) (Exynos chipsets) software. There is a Buffer Overflow in the Touch Screen Driver. The Samsung ID is SVE-2019-14990 (October 2019).
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Analysis
by VulDB Data Team • 10/04/2020
The vulnerability CVE-2019-20558 represents a critical buffer overflow flaw within the touchscreen driver component of Samsung mobile devices running Android versions 7.x, 8.x, and 9.0 specifically on Exynos chipsets. This issue was officially acknowledged by Samsung under their internal security vulnerability tracking system with the identifier SVE-2019-14990 and reported in October 2019. The buffer overflow condition occurs at the kernel level within the touchscreen driver subsystem, which processes input events from the capacitive touch sensors that form the primary user interface for these mobile devices.
The technical flaw manifests when the touchscreen driver fails to properly validate input data received from the hardware sensor components during touch event processing. This inadequate bounds checking allows malicious input data to overflow allocated memory buffers, potentially overwriting adjacent memory regions with arbitrary data. The vulnerability resides in the kernel-space driver code responsible for handling touch input events, making it particularly dangerous as it operates with elevated privileges and can directly manipulate system resources. According to CWE classification, this represents a classic buffer overflow vulnerability categorized under CWE-121, which involves heap-based buffer overflow conditions that can lead to arbitrary code execution.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it creates potential attack vectors for privilege escalation and system compromise. An attacker could potentially exploit this buffer overflow to execute arbitrary code within the kernel context, thereby gaining full control over the device's operating system. This would enable malicious actors to install persistent backdoors, access encrypted data storage, modify system files, and potentially establish a foothold for further lateral movement within network environments. The vulnerability affects millions of devices simultaneously, given the widespread deployment of Exynos chipsets in Samsung's smartphone lineup, making it particularly attractive to threat actors seeking large-scale exploitation opportunities.
Mitigation strategies for CVE-2019-20558 should prioritize immediate patch deployment through Samsung's official security updates, which typically address the root cause by implementing proper bounds checking and input validation within the touchscreen driver code. Organizations and individual users must ensure their devices receive the relevant security patches promptly, as the window for exploitation remains open until remediation is complete. Additionally, network administrators should consider implementing device monitoring solutions that can detect anomalous touchscreen behavior patterns that might indicate exploitation attempts. From a defensive standpoint, the vulnerability aligns with ATT&CK technique T1068, which involves exploiting local privileges to escalate access, and T1203, which covers exploitation of software vulnerabilities. The recommended security controls include maintaining up-to-date device firmware, implementing mobile device management policies, and conducting regular security assessments of mobile endpoints to prevent exploitation of such kernel-level vulnerabilities.