New Chrome Malware Locks Users In Fullscreen Mode: How To Escape And Protect Your System

A newly discovered Google Chrome malware is causing users to lose access to their systems while preventing them from using other applications. Known as ‘ StealC ,’ this malware employs a tactic called the “AutoIt Credential Flusher,” requiring victims to input their Google account details to continue using their computers.

Cybersecurity researchers at OALABS identified this technique, revealing that it has been active in the wild since August 22. The malware has been distributed via traditional malware loaders and information-stealing software like Amadey.

How StealC Locks Chrome Users in Fullscreen
The malware exploits Chrome’s Kiosk Mode , a feature typically used for public kiosks and demo terminals to restrict user access. Once activated, it locks the system in a fullscreen Chrome window, disabling standard shortcuts such as F11 and Esc, making it difficult for users to exit.

This mode strips Chrome’s interface of essential elements like the toolbar, navigation buttons, and address bar. The malware then displays a page demanding the victim’s Google account credentials , effectively locking them out until they comply.

Once the user enters their login details, StealC captures the information and transmits it, allowing attackers to steal sensitive credentials.

Ways to Exit Google Chrome’s Kiosk Mode
If your system is affected by StealC, exiting Chrome’s Kiosk mode requires specific shortcuts, as F11 and Esc won't work. You can try using keyboard combinations like “Alt+F4,” “Ctrl+Shift+Esc,” “Ctrl+Alt+Delete,” or “Alt+Tab.” For instance, pressing Alt+F4 closes the currently active window (Google Chrome), while Alt+Tab helps you switch to another app.

If Kiosk mode returns after these steps, opening the Windows Task Manager with Ctrl+Alt+Delete is a helpful next step. Under the Processes tab, locate Google Chrome, right-click on it, and select "End task." Alternatively, use the “Win+R” shortcut to open the Run command, type “cmd,” and run the command “taskkill /IM chrome.exe /F” to force Chrome to close.

What to Do If Nothing Works
If all else fails, you may need to perform a hard reset by pressing and holding the power button to restart the system. Once your device reboots, it’s crucial to run a thorough antivirus scan using either Windows Defender or third-party security software to ensure the malware is removed and your system is clean.