CVE-2019-15436 in A8+
Summary
by MITRE
The Samsung A8+ Android device with a build fingerprint of samsung/jackpot2ltexx/jackpot2lte:8.0.0/R16NW/A730FXXS4BSC2:user/release-keys contains a pre-installed app with a package name of com.samsung.android.themecenter app (versionCode=7000000, versionName=7.0.0.0) that allows other pre-installed apps to perform app installation via an accessible app component. This capability can be accessed by any pre-installed app on the device which can obtain signatureOrSystem permissions that are required by other other pre-installed apps that exported their capabilities to other pre-installed app.
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Analysis
by VulDB Data Team • 02/20/2024
The vulnerability identified as CVE-2019-15436 resides within the Samsung A8+ Android device running Android 8.0.0, specifically affecting the pre-installed Samsung Theme Center application with package name com.samsung.android.themecenter. This security flaw stems from improper permission handling within the device's application framework, where the theme center application exposes functionality that permits other pre-installed applications to perform package installation operations. The vulnerability manifests through the application's component accessibility, which allows signatureOrSystem permissions to be leveraged by other pre-installed applications to access exported capabilities. This design flaw creates an attack surface that could be exploited by malicious actors within the device's pre-installed application ecosystem. The build fingerprint samsung/jackpot2ltexx/jackpot2lte:8.0.0/R16NW/A730FXXS4BSC2 indicates the specific device model and software version where this vulnerability exists, making it particularly relevant to Samsung's Android 8.0.0 implementation. The exposed functionality represents a critical security oversight that undermines the device's application sandboxing mechanisms and permission model.
The technical implementation of this vulnerability involves the theme center application's improper handling of exported components that enable other pre-installed applications to perform package installation operations. When applications with signatureOrSystem permissions attempt to access these exported capabilities, they can effectively bypass normal installation restrictions and potentially install unauthorized applications. This represents a direct violation of Android's security model where applications should not be able to install packages without explicit user consent or proper permission delegation. The vulnerability's exploitation path relies on the inherent trust relationship between pre-installed applications, which should normally be restricted to prevent such cross-application privilege escalation. The exported component functionality creates a backdoor that allows malicious pre-installed applications to gain unauthorized installation capabilities, essentially providing a privilege escalation mechanism that could be leveraged to install arbitrary applications. This flaw falls under the category of improper permission handling and component exposure, which aligns with CWE-276, improper permissions, and CWE-264, permissions, privileges and access controls.
The operational impact of this vulnerability extends beyond simple unauthorized application installation, as it creates a persistent security risk that could be exploited by attackers with access to pre-installed applications or those that can obtain signatureOrSystem permissions. The vulnerability enables a form of privilege escalation that could allow for the installation of malicious applications that might include malware, spyware, or other harmful software. Attackers could potentially leverage this vulnerability to install applications that monitor user activity, steal sensitive information, or compromise the device's overall security posture. The pre-installed nature of the vulnerable application means that users cannot easily remove or disable the component, making the vulnerability persistent and difficult to mitigate without a system update or firmware modification. This vulnerability significantly weakens the device's security model by undermining the principle of least privilege, where applications should only have the minimum permissions necessary to perform their functions. The impact is particularly severe because it affects the device's core security architecture, potentially allowing attackers to gain persistent access to the device's application installation mechanisms.
Mitigation strategies for CVE-2019-15436 should focus on immediate remediation through official firmware updates from Samsung, as the vulnerability exists within the device's core system applications. Device administrators should ensure that all available security patches are applied promptly to address the exposed component functionality. The vulnerability's exposure of exported components suggests that a comprehensive review of all pre-installed applications and their exported capabilities is necessary to identify similar security flaws within the device's application ecosystem. Organizations should implement monitoring procedures to detect unauthorized application installations that might result from this vulnerability, particularly in enterprise environments where Samsung A8+ devices are deployed. The security community should consider this vulnerability as part of broader Android security assessments, focusing on the proper handling of signatureOrSystem permissions and component exposure. Additionally, users should be advised to avoid installing applications from untrusted sources and to maintain awareness of their device's security status, as the vulnerability represents a fundamental flaw in the device's permission model that could be exploited in various attack scenarios. This vulnerability demonstrates the importance of proper application sandboxing and the need for continuous security assessments of pre-installed applications within mobile operating systems.