A screen overlay is an Android feature that lets one app draw on top of another app’s interface. It is useful for chat bubbles, accessibility tools, and system-style controls, but it also creates a security boundary problem: the overlay can hide, alter, or visually confuse what the user thinks they are approving. Attackers have abused overlays to cover login screens, fake buttons, or warnings, making a trusted app appear to say something else.
In cyber security, overlays matter because they can support phishing, tapjacking, and prompt-injection-style attacks on mobile workflows. If an AI agent or human operator reads the visible screen without validating the underlying app state, hidden overlay text can steer decisions. Defenders reduce risk by limiting overlay permissions, warning on sensitive actions, and requiring explicit confirmation from the real app rather than from whatever is drawn on top.