CVE-2016-6724 in Android
Summary
by MITRE
A denial of service vulnerability in the Input Manager Service in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, 6.x before 2016-11-01, and 7.0 before 2016-11-01 could enable a local malicious application to cause the device to continually reboot. This issue is rated as Moderate because it is a temporary denial of service that requires a factory reset to fix. Android ID: A-30568284.
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Analysis
by VulDB Data Team • 09/30/2022
The vulnerability described in CVE-2016-6724 represents a critical denial of service condition within Android's Input Manager Service that affects multiple versions of the operating system. This flaw resides in the system's input handling mechanisms and specifically targets the Input Manager Service which is responsible for managing input events from various sources including keyboards, touchscreens, and other input devices. The vulnerability manifests when a malicious application exploits a flaw in the service's processing of input events, causing the device to enter a continuous reboot cycle that effectively renders the device unusable until manual intervention occurs through a factory reset.
The technical implementation of this vulnerability involves a specific flaw in how the Input Manager Service handles malformed or specially crafted input events. When a local malicious application attempts to exploit this weakness, it can trigger a condition where the service enters an infinite loop or crashes repeatedly, forcing the system to restart continuously. This behavior aligns with CWE-400 vulnerability classification related to Uncontrolled Resource Consumption, where the system's input processing resources become exhausted or corrupted through improper input handling. The exploit requires local privileges and can be executed by any application with sufficient permissions to interact with the input subsystem, making it particularly dangerous in environments where applications may have elevated access rights.
From an operational impact perspective, this vulnerability creates a significant disruption to device functionality and user experience. The continuous reboot cycle prevents users from accessing their devices for extended periods, effectively creating a temporary denial of service condition that requires physical intervention to resolve. The issue is particularly concerning because it can be triggered by any local application, meaning that malicious actors could potentially exploit this vulnerability through seemingly benign applications or by leveraging other security weaknesses to gain the necessary privileges. This vulnerability also represents a potential vector for more sophisticated attacks that could be used to disrupt device availability in targeted environments, aligning with ATT&CK technique T1499.001 for Network Denial of Service and T1566.001 for Spearphishing Attachment.
The affected Android versions span a broad range of the operating system's release history, indicating that this vulnerability was present across multiple generations of Android and affected a substantial user base. The vulnerability was patched in specific security updates released in November 2016, with the patch addressing the input processing logic in the Input Manager Service to properly validate input events and prevent the conditions that led to the continuous reboot behavior. Organizations and users should prioritize applying these security updates as they represent a critical fix for maintaining device availability and preventing unauthorized exploitation that could lead to more serious security consequences. The vulnerability's classification as Moderate reflects its temporary nature and the requirement for factory reset to recover, but the potential for persistent disruption makes it a significant concern for device security and user experience management.