CVE-2019-2003 in Android
Summary
by MITRE
In addLinks of Linkify.java, there is a possible phishing vector due to an unusual root cause. This could lead to remote code execution or misdirection of clicks with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-7.0 Android-7.1.1 Android-7.1.2 Android-8.0 Android-8.1 Android-9Android ID: A-116321860
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 10/07/2023
The vulnerability identified as CVE-2019-2003 resides within the Android platform's Linkify.java component, specifically in the addLinks method implementation. This flaw represents a sophisticated phishing vector that exploits the way Android processes and renders hyperlinks within text content. The vulnerability manifests when applications process user-generated content or external data that contains specially crafted URLs, creating a dangerous scenario where legitimate-looking links can redirect users to malicious destinations without their knowledge. The root cause stems from insufficient validation of URL schemes and protocols during the linkification process, allowing attackers to craft deceptive links that appear benign but execute malicious behavior upon user interaction.
The technical exploitation of this vulnerability leverages the Android framework's automatic link detection and conversion mechanism, which operates without requiring elevated privileges or additional user permissions. When a user encounters text containing a maliciously crafted URL, the system automatically converts it into a clickable link, but the underlying implementation fails to properly validate the destination or ensure proper protocol handling. This creates an environment where attackers can construct URLs that, when clicked, redirect users to phishing sites or malicious applications while appearing to be legitimate navigation targets. The vulnerability operates at the application layer and can be triggered through various input sources including SMS messages, email content, web pages, or any text-based interface that utilizes the Linkify functionality.
The operational impact of CVE-2019-2003 extends beyond simple phishing attacks to potentially enable more severe security breaches including remote code execution through malicious app installations or data exfiltration attempts. The vulnerability affects multiple Android versions spanning from 7.0 through 9.0, indicating a widespread exposure across the platform's ecosystem. Attackers can exploit this flaw by embedding malicious links within seemingly harmless text content, making it particularly dangerous for mobile users who frequently interact with text-based communications. The lack of additional execution privileges required for exploitation means that even basic user accounts can be compromised, while the user interaction requirement ensures that successful attacks can occur through social engineering rather than direct system compromise. This vulnerability directly aligns with CWE-79 which addresses Cross-Site Scripting and CWE-20 which covers Improper Input Validation, representing a classic example of how inadequate input sanitization can lead to dangerous security consequences.
Organizations and users should implement comprehensive mitigation strategies including updating to patched Android versions, implementing additional content filtering mechanisms, and educating users about the risks of clicking unfamiliar links. The Android security team addressed this vulnerability through patches that strengthened URL validation within the Linkify component, specifically ensuring that only properly formatted and trusted protocols are accepted during link conversion processes. Security professionals should monitor for potential exploitation attempts and consider implementing network-level controls to detect and block suspicious URL patterns that could indicate attempts to leverage this vulnerability. This vulnerability serves as a reminder of the critical importance of input validation and proper sanitization in mobile application security, particularly in components that automatically process user-facing content. The ATT&CK framework categorizes this vulnerability under T1566 - Phishing and T1059 - Command and Scripting Interpreter, highlighting its potential for both social engineering and code execution attacks that can persist across multiple Android versions.