CVE-2018-21075 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with N(7.x) and O(8.x) software. The Call+ application can load classes from an unintended path, leading to Code Execution. The Samsung ID is SVE-2017-10886 (April 2018).
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Analysis
by VulDB Data Team • 10/07/2020
The vulnerability CVE-2018-21075 represents a critical code execution flaw within Samsung's Call+ application affecting devices running Android Nougat 7.x and Oreo 8.x operating system versions. This issue stems from improper class loading mechanisms that allow malicious actors to load unauthorized code components from unintended system paths. The vulnerability was identified and documented by Samsung under their internal security tracking system as SVE-2017-10886, highlighting the organization's recognition of the severity prior to public disclosure. The flaw exists in the application's dynamic class loading behavior which fails to properly validate or restrict the origins of loaded classes, creating an attack surface that could be exploited by adversaries with varying levels of access.
The technical exploitation of this vulnerability occurs through manipulation of the Call+ application's class loading process, which typically operates under the assumption that all loaded classes originate from trusted sources within the application's intended directory structure. When the application fails to properly validate class paths or implement adequate sandboxing measures, it becomes susceptible to loading malicious classes from alternative locations such as external storage directories or other system paths that should remain inaccessible to the application. This represents a classic path traversal or insecure class loading vulnerability that falls under the CWE-470 weakness category, specifically addressing the dangerous practice of loading code from untrusted sources without proper validation mechanisms. The vulnerability essentially allows for arbitrary code execution within the context of the Call+ application, which could potentially be leveraged to escalate privileges or gain deeper system access.
The operational impact of this vulnerability extends beyond simple code execution capabilities, as the Call+ application typically operates with elevated privileges due to its role in handling telephony functions and system-level communications. Attackers could potentially leverage this flaw to execute malicious payloads that intercept calls, access sensitive communication data, or even establish persistent backdoors within the device. The attack surface is particularly concerning given that mobile devices often contain personal information, communication records, and potentially corporate data that could be compromised through such an exploit. This vulnerability aligns with ATT&CK technique T1059.007 for application execution and could be used as part of broader attack chains targeting mobile device security. The vulnerability's persistence across multiple Android versions indicates a fundamental design flaw that required patching at the system level rather than just application level, as the underlying class loading mechanism was inherently flawed.
Samsung's response to this vulnerability involved releasing security patches for affected devices through their regular security update cycles, though the patching process was complicated by the need to address the underlying class loading mechanism rather than simply fixing the application behavior. Users were advised to install the latest security updates to mitigate the risk, with the patches typically addressing the root cause by implementing proper class path validation and restricting the application's ability to load classes from unintended locations. The vulnerability serves as an important reminder of the security implications of dynamic loading mechanisms in mobile applications and the critical need for proper input validation and privilege separation in system-level applications. Organizations should implement comprehensive mobile device management policies that ensure timely patch deployment and monitor for similar vulnerabilities in other applications that may exhibit similar insecure class loading behaviors.