CVE-2021-25354 in Internet
Summary
by MITRE • 03/25/2021
Improper input check in Samsung Internet prior to version 13.2.1.46 allows attackers to launch non-exported activity in Samsung Browser via malicious deeplink.
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Analysis
by VulDB Data Team • 04/05/2021
The vulnerability identified as CVE-2021-25354 represents a critical input validation flaw within Samsung Internet browser prior to version 13.2.1.46 that enables attackers to exploit deep link mechanisms to launch non-exported activities within the Samsung Browser application. This issue falls under the category of improper input validation as defined by CWE-20, where the application fails to properly validate and sanitize user-supplied input before processing it. The vulnerability specifically affects the deep link handling mechanism that allows external applications to communicate with Samsung Internet through intent-based navigation.
The technical flaw manifests when Samsung Internet processes malicious deep links that contain specially crafted parameters designed to bypass normal security boundaries. These deep links can trigger the launch of internal activities that are not intended to be publicly accessible or exported, effectively allowing attackers to execute code or access restricted functionality within the browser application. The vulnerability stems from insufficient validation of intent parameters and URI schemes that should normally be restricted to internal use only. This improper handling creates an attack surface where malicious actors can leverage the browser's deep link infrastructure to gain unauthorized access to internal components.
The operational impact of this vulnerability extends beyond simple privilege escalation as it enables attackers to potentially execute arbitrary code within the context of the Samsung Browser application. Attackers can craft malicious deep links that, when clicked by a victim, trigger the launch of non-exported activities that may contain sensitive functionality or data access points. This could lead to information disclosure, unauthorized access to user data, or even full system compromise depending on the privileges and capabilities of the launched activities. The vulnerability is particularly dangerous because it operates at the application level and leverages the trust relationships between components within the Samsung Internet application framework, as described in the ATT&CK framework under technique T1059 for executing malicious code.
The exploitation of this vulnerability requires minimal user interaction and can be delivered through various attack vectors including phishing emails, malicious websites, or compromised applications that can generate the malicious deep links. Security researchers have noted that the vulnerability is particularly concerning because it operates in a manner consistent with the ATT&CK technique T1190 for exploitation of remote services through malicious links. The affected Samsung Internet versions prior to 13.2.1.46 represent a significant security gap where the application's intent filtering mechanisms fail to properly validate the source and content of incoming deep link requests, creating an opportunity for attackers to bypass normal application security controls.
Mitigation strategies for CVE-2021-25354 primarily focus on updating to Samsung Internet version 13.2.1.46 or later, which includes proper input validation and intent filtering mechanisms. Organizations should also implement network-level controls to block suspicious deep link patterns and educate users about the risks of clicking untrusted links. The vulnerability highlights the importance of proper intent validation in Android applications and reinforces the need for comprehensive security testing of inter-component communication mechanisms. Additionally, system administrators should monitor for any unauthorized activity that might indicate exploitation attempts and ensure that all mobile applications are kept up to date with the latest security patches. The fix implemented by Samsung addresses the root cause by strengthening the input validation process and ensuring that only properly authorized activities can be launched through deep link mechanisms, thereby preventing unauthorized access to internal application components as recommended by industry security best practices.