CVE-2021-39691: WindowManager.LayoutParams.FLAG_SLIPPERY allows for bypass of MotionEvent.FLAG_WINDOW_IS_PARTIALLY_OBSCURED
Summary
CVE-2021-39691: In WindowManager, there is a possible tapjacking attack due to an incorrect window flag when processing user input. Affects platform/frameworks/base across 3 version ranges.
>= 11:0, < 11:2022-06-01
>= 12:0, < 12:2022-06-01
>= 12L-next:0, < 12L-next:2022-06-01
Fixed in 12L-next:2022-06-01. How to fix ↓
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Background
The WindowManager is a class in the Android framework that provides access to the system window manager. It is responsible for managing the layout and appearance of windows on the screen. The WindowManager.LayoutParams.FLAG_SLIPPERY flag is used to indicate that a window should be slippery, which means that it can be dragged off the screen. This flag is typically used for system windows that are not meant to be interacted with by the user. However, due to an incorrect window flag when processing user input, a tapjacking attack is possible, allowing an attacker to manipulate user input and potentially escalate privileges.
Vulnerability Detail
The vulnerability (CVE-2021-39691) arises from an incorrect window flag in the WindowManager when processing user input. By exploiting this vulnerability, an attacker can perform a tapjacking attack, where they overlay a malicious window on top of a legitimate window and trick the user into interacting with the malicious window instead. This can lead to local escalation of privilege, as the attacker can perform actions on behalf of the user without their knowledge or consent. The vulnerability affects Android versions 10, 11, and 12.
How To Fix
Minimum fixed version
12L-next:2022-06-01
This is the first release that contains the fix.
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Workaround
There is no known workaround for this vulnerability. It is recommended to apply the fix provided by the Android security update.
Conclusion
The WindowManager vulnerability (CVE-2021-39691) allows for a tapjacking attack on Android devices running versions 10, 11, and 12. This can lead to local escalation of privilege and unauthorized actions performed on behalf of the user. It is crucial to update to the latest version of Android that includes the fix to mitigate this vulnerability. For further support on vulnerability remediation, please contact DevNack.com.
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FAQ
WindowManager is a class in the Android framework that manages the layout and appearance of windows on the screen.
Tapjacking is a type of attack where an attacker overlays a malicious window on top of a legitimate window and tricks the user into interacting with the malicious window instead.
This vulnerability allows an attacker to perform a tapjacking attack and potentially escalate privileges on the affected Android device.
Android versions 10, 11, and 12 are affected by this vulnerability.
No, there is no known workaround for this vulnerability. It is recommended to apply the fix provided by the Android security update.
References
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