CVE-2018-21074 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with M(6.x) (Exynos or Qualcomm chipsets) software. There is information disclosure from a Trustlet via the debug log. The Samsung ID is SVE-2017-10638 (April 2018).
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Analysis
by VulDB Data Team • 10/07/2020
This vulnerability affects Samsung mobile devices running Android 6.x operating system with either Exynos or Qualcomm chipsets. The issue stems from improper handling of debug logging mechanisms within the Trustlet component, which represents a security-sensitive subsystem that operates in a trusted execution environment. Trustlets are lightweight applications that run within the secure element of mobile devices and are designed to handle cryptographic operations and sensitive data processing. The vulnerability allows unauthorized information disclosure through debug log outputs that should normally be restricted to authorized personnel only.
The technical flaw manifests in the Trustlet's debug logging functionality where sensitive information flows through debug output channels without proper sanitization or access controls. This represents a violation of the principle of least privilege and demonstrates inadequate separation between secure and non-secure execution contexts. The vulnerability is categorized under CWE-200 Information Disclosure, specifically involving improper restriction of information flow through debug mechanisms. When debug logs are generated by the Trustlet component, they contain sensitive data that should remain protected within the secure execution environment, creating a potential information leak that could expose cryptographic keys, authentication tokens, or other confidential processing results.
The operational impact of this vulnerability extends beyond simple information disclosure, as it potentially enables attackers to extract sensitive data from the secure execution environment where Trustlets operate. This weakness could be exploited by malicious applications or attackers with physical access to the device to gather information that would normally remain protected within the secure element. The vulnerability affects the fundamental security model of Samsung's mobile platform, undermining the trust assumptions that users and developers place in secure execution environments. Attackers could leverage this information disclosure to perform further attacks including cryptographic key recovery, authentication bypass, or other advanced persistent threats that exploit the leaked information to compromise the device's security posture.
Security mitigations for this vulnerability should focus on implementing proper access controls for debug logging mechanisms within Trustlet components and ensuring that sensitive information is never output to debug channels under any circumstances. The solution requires enforcement of secure coding practices that prevent information flow from secure to non-secure contexts through debug mechanisms. Device manufacturers should implement runtime checks that sanitize debug output and enforce strict access controls for debug interfaces. Additionally, system-level protections should be implemented to prevent unauthorized access to debug logs and ensure that any sensitive data processing within Trustlets remains isolated from potentially compromised application environments. This vulnerability aligns with ATT&CK technique T1059.001 Command and Scripting Interpreter: PowerShell, where debug interfaces represent potential attack vectors for information extraction. The remediation should include comprehensive code review processes that specifically target secure execution environment boundaries and ensure proper isolation between trusted and non-trusted components.