CVE-2017-0492 in Android
Summary
by MITRE
An elevation of privilege vulnerability in the System UI could enable a local malicious application to create a UI overlay covering the entire screen. This issue is rated as Moderate because it is a local bypass of user interaction requirements that would normally require either user initiation or user permission. Product: Android. Versions: 7.1.1. Android ID: A-30150688.
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Analysis
by VulDB Data Team • 09/05/2020
The vulnerability identified as CVE-2017-0492 represents a critical elevation of privilege flaw within the Android System UI component that allows malicious applications to manipulate the user interface overlay functionality. This security weakness exists in Android version 7.1.1 and stems from insufficient access controls and validation mechanisms within the system's UI rendering subsystem. The vulnerability specifically targets the permission model that governs how applications can overlay content on top of other applications, creating a potential attack vector that bypasses normal user interaction requirements. According to the Android security advisory A-30150688, this issue enables a local attacker to craft a malicious application that can establish a full-screen UI overlay without proper user consent or explicit permission granting.
The technical implementation of this vulnerability involves exploiting a flaw in the Android System UI's handling of window manager permissions and overlay display capabilities. When an application attempts to create a UI overlay, the system should verify that the application has proper authorization and that the overlay request meets security requirements. However, in this case, the vulnerability allows an attacker to bypass these checks through improper validation of overlay requests. The flaw operates at the system level where UI components interact with the window manager service, creating a scenario where malicious code can manipulate the display layer to cover entire screens without requiring user interaction or explicit permission prompts. This behavior aligns with CWE-284 Access Control flaws that specifically address insufficient access control mechanisms in system-level components.
The operational impact of CVE-2017-0492 extends beyond simple UI manipulation as it creates a foundation for more sophisticated attacks within the Android ecosystem. A malicious application leveraging this vulnerability could potentially capture user input, display fraudulent interfaces to trick users into revealing sensitive information, or interfere with normal application functionality. The local nature of this exploit means that no network connectivity or remote user interaction is required for the attack to succeed, making it particularly dangerous in environments where users may unknowingly install malicious applications. This vulnerability directly affects the Android security model's principle of least privilege, where applications should only be granted the minimum permissions necessary to function properly. The issue is rated as Moderate severity because while it requires local access and doesn't enable immediate remote exploitation, it provides a significant foothold for further attack vectors and can be combined with other vulnerabilities to escalate privileges within the system.
Mitigation strategies for this vulnerability should focus on both immediate system updates and enhanced application security practices. Android users and administrators should immediately apply the relevant security patches and updates provided by Google to address the underlying System UI flaw. The fix typically involves strengthening the permission validation mechanisms within the window manager service and ensuring proper access controls are enforced when processing overlay requests. Organizations should also implement application whitelisting policies and monitor for suspicious overlay behavior in their managed environments. From a defensive perspective, this vulnerability demonstrates the importance of secure UI component design and proper access control implementation, aligning with ATT&CK technique T1056 Input Capture which covers methods of capturing user input through UI manipulation. Security professionals should also consider implementing behavioral monitoring solutions that can detect anomalous overlay creation patterns that may indicate exploitation attempts. The vulnerability underscores the need for continuous security assessments of system-level components and highlights the critical importance of maintaining up-to-date security patches across all Android devices to prevent exploitation of such fundamental access control flaws.