CVE-2020-0475 in Android
Summary
by MITRE • 12/15/2020
In createInputConsumer of WindowManagerService.java, there is a possible way to block and intercept input events due to a missing permission check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-162324374
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Analysis
by VulDB Data Team • 12/18/2020
The vulnerability identified as CVE-2020-0475 resides within the Android system's WindowManagerService.java component, specifically in the createInputConsumer method where a critical permission check is absent. This flaw represents a significant security weakness that allows malicious applications to potentially intercept and block input events, effectively creating a pathway for unauthorized system control. The vulnerability is classified as a local privilege escalation issue, meaning that an attacker with minimal privileges can exploit this weakness to gain elevated system access without requiring additional execution privileges or root access.
The technical implementation of this vulnerability stems from the absence of proper authorization validation within the input event handling mechanism. When applications attempt to create input consumers through the WindowManagerService, the system fails to verify whether the requesting component possesses the necessary permissions to perform such operations. This missing permission check creates an attack surface where malicious applications can manipulate the input event flow, potentially capturing sensitive user interactions or preventing legitimate applications from receiving input events. The vulnerability's classification aligns with CWE-284, which addresses improper access control mechanisms, and demonstrates how insufficient authorization checks can lead to privilege escalation scenarios.
From an operational perspective, this vulnerability poses a substantial risk to Android device security as it enables attackers to intercept user input events, potentially capturing passwords, PINs, or other sensitive information entered by users. The requirement for user interaction indicates that exploitation typically occurs through social engineering or when users inadvertently grant malicious applications the necessary permissions to exploit this weakness. The attack vector is particularly concerning because it operates at the system level within the window management service, making it difficult to detect and mitigate without proper security controls. This vulnerability affects Android 11 systems and represents a critical concern for device security and user privacy protection.
The exploitation of CVE-2020-0475 aligns with several tactics described in the MITRE ATT&CK framework, particularly those related to privilege escalation and credential access. Attackers can leverage this weakness to establish persistent input interception capabilities, potentially enabling them to monitor user activities and capture authentication credentials. The lack of additional execution privileges required for exploitation makes this vulnerability particularly dangerous as it can be exploited by applications with minimal initial access. Security mitigations should focus on implementing proper permission validation within the WindowManagerService, ensuring that all input consumer creation operations require appropriate authorization checks. Organizations should also consider applying security patches promptly and implementing monitoring solutions to detect unauthorized input interception activities. The vulnerability underscores the importance of comprehensive permission validation across all system components and highlights the critical need for robust access control mechanisms in mobile operating systems.