CVE-2018-21083 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with M(6.0), N(7.x), and O(8.0) (Exynos or Qualcomm chipsets) software. There is information disclosure (of a kernel address) via trustonic_tee. The Samsung ID is SVE-2017-11175 (February 2018).
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Analysis
by VulDB Data Team • 10/09/2020
This vulnerability resides within the Trustonic Trusted Execution Environment (TEE) implementation on Samsung mobile devices running Android versions 6.0, 7.x, and 8.0. The issue manifests as an information disclosure flaw that reveals kernel addresses through the trustonic_tee subsystem, which operates within the secure enclave environment. The vulnerability affects devices equipped with either Exynos or Qualcomm chipsets, indicating a widespread impact across Samsung's hardware portfolio during this software era. The disclosure of kernel addresses represents a significant security concern as it provides attackers with critical information about the system's memory layout and kernel structure.
The technical flaw stems from improper handling of kernel memory addresses within the TEE communication interfaces. When the trustonic_tee component processes certain requests or operations, it inadvertently exposes kernel virtual addresses to unprivileged userspace applications or potentially malicious entities operating within the TEE environment. This information disclosure occurs through specific API calls or data structures that are meant to remain protected within the kernel space. The vulnerability falls under CWE-200, which specifically addresses improper exposure of sensitive information, and aligns with ATT&CK technique T1059.003 for execution through kernel modules and T1068 for privilege escalation via kernel exploits. The flaw represents a failure in information hiding principles where kernel memory addresses should remain confidential and protected from unauthorized access.
The operational impact of this vulnerability extends beyond simple information disclosure, as kernel address exposure can facilitate more sophisticated attacks including privilege escalation and kernel exploitation. Attackers who obtain these kernel addresses can use them to bypass kernel address space layout randomization (ASLR) protections, making subsequent exploitation attempts significantly more effective. The vulnerability affects the integrity of the TEE environment by undermining the confidentiality guarantees that secure enclaves are designed to provide. This disclosure creates opportunities for attackers to understand the kernel's memory organization, potentially enabling them to craft more precise exploits against other kernel components or to predict memory layouts for advanced attack vectors.
Mitigation strategies should focus on both immediate patching and architectural improvements to prevent similar issues. Samsung's security advisory SVE-2017-11175 should be implemented promptly across affected devices, though this may not be feasible for older hardware. System administrators should consider disabling unnecessary TEE functionality where possible and implement additional monitoring for suspicious TEE access patterns. The vulnerability demonstrates the importance of proper kernel memory management and the need for comprehensive security testing of trusted execution environments. Organizations should also consider implementing runtime protection mechanisms such as kernel memory protection and enhanced access controls for TEE interfaces. The issue highlights the critical need for secure coding practices in kernel-level components and emphasizes the necessity of thorough security reviews for all system interfaces that handle sensitive data, particularly those operating within secure execution environments that are expected to provide strong confidentiality guarantees.