CVE-2019-20587 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with O(8.1) and P(9.0) (with TEEGRIS) software. There is type confusion in the MLDAP Trustlet, leading to arbitrary code execution. The Samsung ID is SVE-2019-14867 (August 2019).
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Analysis
by VulDB Data Team • 10/04/2020
The vulnerability CVE-2019-20587 represents a critical type confusion flaw within the MLDAP Trustlet component of Samsung's TEEGRIS security framework, affecting devices running Android 8.1 and 9.0 operating systems. This issue resides within the Trusted Execution Environment (TEE) implementation, specifically targeting the MLDAP (Mobile LDAP) Trustlet that handles authentication and secure credential management. The vulnerability was identified and documented by Samsung under their internal security vulnerability tracking system as SVE-2019-14867, highlighting the severity of the flaw within their security architecture.
The technical root cause of this vulnerability stems from improper type validation within the MLDAP Trustlet's memory management routines, creating a type confusion scenario that allows attackers to manipulate object types during runtime execution. When the Trustlet processes certain input parameters, it fails to properly validate the expected data types, enabling an attacker to craft malicious input that causes the system to treat one data type as another. This type confusion vulnerability falls under CWE-188, which specifically addresses the improper handling of data type conversions, and represents a classic example of how insufficient input validation in secure execution environments can lead to complete system compromise. The flaw exists in the Trustlet's handling of memory objects, where the system's type checking mechanisms are bypassed or misimplemented.
The operational impact of this vulnerability is severe and far-reaching, as it provides attackers with arbitrary code execution capabilities within the Trusted Execution Environment. This means that an attacker who successfully exploits this vulnerability can execute malicious code with the elevated privileges and access rights that the TEE is designed to protect against. The attack surface is particularly concerning because the MLDAP Trustlet is responsible for managing sensitive authentication credentials and secure key storage, making this vulnerability a prime target for attackers seeking to escalate privileges or extract confidential information from the device's secure storage. The TEEGRIS framework's purpose is to isolate sensitive operations from the main operating system, but this vulnerability effectively undermines that isolation, creating a direct path to compromise the device's security architecture.
Mitigation strategies for CVE-2019-20587 should prioritize immediate patch deployment through Samsung's security update mechanisms, as the vulnerability affects multiple device models across the Samsung ecosystem. Organizations and users should ensure that all affected Samsung devices receive the relevant security patches released by Samsung, which typically include updated versions of the TEEGRIS framework and the MLDAP Trustlet component. The vulnerability's classification as a type confusion issue aligns with ATT&CK technique T1068, which describes the exploitation of local privilege escalation vulnerabilities, and attackers may leverage this flaw as part of broader exploitation chains targeting mobile device security. Additionally, network administrators should implement monitoring for suspicious authentication patterns and credential access attempts that might indicate exploitation attempts, while security teams should consider the broader implications for mobile device management and enterprise security policies.