CVE-2020-35549 in Mobile Device
Summary
by MITRE • 12/18/2020
An issue was discovered on Samsung mobile devices with O(8.x), P(9.0), and Q(10.0) software. Any application may establish itself as the default dialer, without user interaction. The Samsung ID is SVE-2020-19172 (December 2020).
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Analysis
by VulDB Data Team • 12/18/2020
This vulnerability affects Samsung mobile devices running operating system versions Oreo 8.x, Pie 9.0, and Q 10.0, representing a critical security flaw in the Android-based smartphone platform. The issue allows any application to assume the role of default dialer without requiring explicit user consent or interaction, creating a significant attack vector for malicious actors seeking to compromise device security and user privacy. The Samsung ID SVE-2020-19172 identifies this specific weakness within the company's vulnerability tracking system.
The technical flaw stems from inadequate permission controls and validation mechanisms within Samsung's implementation of the Android dialer application framework. Normally, Android systems require explicit user confirmation when applications request to become default handlers for specific intents such as phone calls or dialing operations. However, this vulnerability bypasses these standard security checks, allowing any malicious application to programmatically assume the default dialer role through improper privilege escalation or insufficient access control validation. This behavior violates fundamental security principles of user consent and application permission management.
The operational impact of this vulnerability extends far beyond simple inconvenience, creating multiple attack surfaces for threat actors. Once an application becomes the default dialer, it gains elevated privileges to intercept, monitor, and potentially manipulate all incoming and outgoing phone calls. Attackers could leverage this capability to conduct call interception, gather sensitive personal information, redirect calls to malicious numbers, or even implement spyware functionality without user knowledge. The vulnerability effectively undermines the Android security model's principle of least privilege and user consent, making it particularly dangerous for users who may unknowingly install compromised applications.
From a cybersecurity perspective, this vulnerability aligns with CWE-284 (Improper Access Control) and maps to ATT&CK technique T1546.001 (Event Triggered Execution: Change Default Application). The flaw represents a privilege escalation issue that allows malicious applications to gain system-level capabilities without proper authorization. Organizations and individuals should consider this vulnerability as part of broader mobile security assessments, particularly in enterprise environments where device management and user privacy are paramount concerns.
Recommended mitigations include immediate software updates from Samsung addressing the specific vulnerability, implementation of application blacklisting or whitelisting policies on managed devices, and enhanced monitoring for unauthorized default application changes. Users should exercise extreme caution when installing applications and regularly verify their device's default application settings. Network administrators should consider deploying mobile device management solutions that can detect and prevent unauthorized default application modifications, while also ensuring comprehensive patch management programs are in place to address similar vulnerabilities across the enterprise environment.