CVE-2018-21044 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with N(7.x) and O(8.0) software. The sem Trustlet has a buffer overflow that leads to arbitrary TEE code execution. The Samsung IDs are SVE-2018-13230, SVE-2018-13231, SVE-2018-13232, SVE-2018-13233 (December 2018).
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Analysis
by VulDB Data Team • 10/07/2020
The vulnerability identified as CVE-2018-21044 represents a critical buffer overflow flaw within the Samsung sem Trustlet component affecting devices running Android Nougat 7.x and Oreo 8.0 operating system versions. This issue resides within the Trusted Execution Environment (TEE) infrastructure that Samsung employs to protect sensitive operations and data processing. The sem Trustlet serves as a crucial security component that handles cryptographic operations and secure key storage, making it a prime target for attackers seeking to compromise the device's security posture. The vulnerability was disclosed through Samsung's internal security tracking system with IDs SVE-2018-13230 through SVE-2018-13233, indicating a coordinated disclosure approach that aligns with industry best practices for vulnerability management.
The technical flaw manifests as a classic buffer overflow condition within the Trustlet implementation where insufficient input validation allows an attacker to write beyond allocated memory boundaries. This memory corruption vulnerability specifically affects the TEE execution environment, which operates in a separate security domain from the main Android OS and is designed to provide hardware-level security guarantees. The overflow occurs during processing of untrusted input data that flows into the Trustlet service, potentially allowing an attacker to manipulate memory layout and execute arbitrary code within the TEE context. This represents a significant escalation from typical Android application-level vulnerabilities since it operates within the trusted security domain where sensitive operations should remain isolated from regular application threats.
The operational impact of this vulnerability extends beyond simple privilege escalation as it fundamentally undermines the security model of Samsung's TEE implementation. Attackers who successfully exploit this buffer overflow can achieve complete control over the Trusted Execution Environment, potentially gaining access to cryptographic keys, secure storage areas, and other sensitive data that the TEE is specifically designed to protect. The vulnerability affects devices running Android 7.x and 8.0 versions, representing a substantial user base that would be impacted by such a flaw. This type of attack vector directly contradicts the fundamental security principles established by the Common Weakness Enumeration framework under CWE-121, which categorizes buffer overflow conditions as critical weaknesses that can lead to arbitrary code execution.
Security implications of this vulnerability align with ATT&CK framework techniques that target system-level compromises, specifically mapping to T1059.007 for command and scripting interpreter execution within trusted environments. The vulnerability enables attackers to bypass traditional Android security controls and operate within the TEE domain where normal application sandboxing does not apply. This creates a persistent threat vector that could remain undetected while providing attackers with access to sensitive operations that should remain protected. The exploitation of such vulnerabilities in TEE components represents a sophisticated attack approach that targets the foundational security architecture of mobile devices, potentially enabling advanced persistent threats that can maintain long-term access to device security features.
Mitigation strategies for this vulnerability require immediate firmware updates from Samsung as the primary defense mechanism, since the flaw exists at the system-level component that cannot be patched through regular application updates. Users should ensure their devices receive the security patches released by Samsung following the vulnerability disclosure, as these updates typically include memory boundary checks and input validation improvements within the Trustlet implementation. Network-based detection measures can identify potential exploitation attempts through monitoring for unusual Trustlet communications or memory access patterns, though the nature of TEE exploitation makes such detection challenging. Device manufacturers and security researchers should also consider implementing additional runtime protections and memory integrity checks that could help detect or prevent exploitation attempts targeting similar TEE vulnerabilities. The vulnerability serves as a reminder of the critical importance of secure coding practices in TEE implementations and the need for comprehensive security testing of trusted execution environments to prevent such fundamental architecture flaws that can compromise the entire device security model.