CVE-2019-20562 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with P(9.0) (with TEEGRIS) software. There is a buffer overflow in the BIOSUB Trustlet. The Samsung ID is SVE-2019-15264 (October 2019).
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Analysis
by VulDB Data Team • 10/04/2020
The vulnerability identified as CVE-2019-20562 represents a critical buffer overflow condition within the BIOSUB Trustlet component of Samsung mobile devices running Android 9.0 with TEEGRIS software. This flaw exists within the Trusted Execution Environment (TEE) architecture, specifically affecting the Secure World subsystem that handles sensitive operations and cryptographic functions. The buffer overflow occurs in the BIOSUB Trustlet which serves as a critical interface between the normal world and the secure world of the device's security architecture, making it a prime target for exploitation by malicious actors seeking to compromise the device's security boundaries.
The technical implementation of this vulnerability stems from improper bounds checking within the BIOSUB Trustlet's input validation mechanisms. When processing certain data inputs, the trustlet fails to adequately verify buffer boundaries, allowing an attacker to write beyond allocated memory regions. This condition typically arises from insufficient validation of input parameters passed to the trustlet through the Trusted Application Interface, where malicious data can trigger memory corruption that may lead to arbitrary code execution within the secure environment. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which directly impacts the integrity of the TEE's memory management and can potentially allow privilege escalation attacks.
The operational impact of this vulnerability extends beyond simple local exploitation, as it compromises the fundamental security model of Samsung's mobile devices. Attackers who successfully exploit this buffer overflow can potentially gain unauthorized access to the secure world environment, where sensitive cryptographic keys, biometric data, and other protected information are stored and processed. This weakness enables attackers to bypass the security boundaries established by the TEE architecture, undermining the device's overall security posture and potentially allowing for full device compromise. The vulnerability affects devices with TEEGRIS software, which represents Samsung's implementation of the Trusted Execution Environment for their mobile platforms, making it particularly concerning for enterprise and government deployments where device security is paramount.
Mitigation strategies for this vulnerability require immediate firmware updates from Samsung, as the fix typically involves patching the BIOSUB Trustlet with proper bounds checking and input validation routines. Organizations should implement comprehensive device management policies to ensure all affected devices receive security updates promptly, as the vulnerability exists at the system firmware level and cannot be addressed through standard application-level patches. Security professionals should also consider implementing network monitoring solutions to detect potential exploitation attempts targeting this specific vulnerability, as the attack surface includes both local and remote exploitation vectors. The remediation process should follow established security protocols including vulnerability assessment, risk evaluation, and coordinated patch deployment to minimize the window of exposure while maintaining device functionality and user access to critical services.