CVE-2019-20563 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with O(8.x) and P(9.0) (with TEEGRIS) software. The SEC_FR trustlet has an out of bounds write. The Samsung ID is SVE-2019-15272 (October 2019).
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Analysis
by VulDB Data Team • 10/04/2020
The vulnerability identified as CVE-2019-20563 represents a critical security flaw within Samsung's Trusted Execution Environment implementation on mobile devices running Android 8.x and 9.0 versions. This issue specifically affects devices that utilize the TEEGRIS security framework, which serves as Samsung's proprietary security layer designed to protect sensitive data and cryptographic operations. The vulnerability resides within the SEC_FR trustlet component, which is responsible for managing secure firmware operations and maintaining the integrity of the device's security infrastructure. This particular flaw manifests as an out-of-bounds write condition that can be exploited to compromise the security boundaries established by the Trusted Execution Environment.
The technical nature of this vulnerability falls under CWE-787, which describes out-of-bounds write conditions that occur when a program writes data past the end of a buffer or array. In the context of the Samsung TEEGRIS implementation, the SEC_FR trustlet fails to properly validate input parameters or buffer boundaries during firmware processing operations. This allows an attacker with access to the device's normal operating system to potentially manipulate memory locations beyond the intended buffer limits, leading to arbitrary code execution within the secure environment. The vulnerability is particularly concerning because it operates within the Trusted Execution Environment where sensitive operations should remain isolated from the regular operating system, making it a critical component of Samsung's security architecture.
The operational impact of this vulnerability extends beyond simple privilege escalation as it fundamentally undermines the security model that the Trusted Execution Environment is designed to provide. Attackers who successfully exploit this out-of-bounds write condition can potentially gain unauthorized access to secure firmware operations, cryptographic keys, and sensitive user data stored within the TEE. This exploitation capability directly violates the core principle of TEE isolation, allowing malicious actors to bypass security controls that should prevent normal applications from accessing protected resources. The vulnerability affects devices running Android 8.x and 9.0 versions, which were widely deployed across Samsung's smartphone and tablet lineup, potentially exposing millions of devices to this security risk.
Mitigation strategies for this vulnerability require immediate firmware updates from Samsung to patch the SEC_FR trustlet implementation and correct the buffer validation logic. Organizations and users should prioritize applying the security patches released by Samsung as soon as possible, as the vulnerability can be exploited without user interaction and may allow for complete compromise of the device's secure environment. Security teams should also implement monitoring for unusual firmware update behavior and potential exploitation attempts within their networks. The vulnerability highlights the importance of proper input validation and buffer management in security-critical components, particularly within Trusted Execution Environments where the consequences of memory corruption can be catastrophic. Additionally, the security community should consider implementing runtime protections and memory integrity checks to detect and prevent similar out-of-bounds write conditions in other security components. This vulnerability serves as a reminder of the critical nature of secure code practices within TEE implementations and the potential for seemingly minor flaws to create significant security risks in mobile device security architectures.