I found a website that claimed I needed to complete a human verification check. After clicking the checkbox, it instructed me to press Win+R and paste a PowerShell command. The command downloads a file from the internet into the Windows temporary folder and then runs it with PowerShell's execution policy bypassed and the window hidden. I closed the site instead of running it, but other family members use this computer, so I'd like to understand what the command could do and how to prevent someone from falling for a similar fake verification prompt.
4 Answers
You did the right thing by closing the page. The command downloads whatever code is hosted at that address, saves it as a PowerShell script, and executes it. Because the downloaded code controls what happens next, it could perform essentially any action allowed under the current Windows account. The hidden window and execution-policy bypass are major warning signs.
If you never pasted or ran the command, the computer was probably not infected by this incident. Still, warn everyone who uses the PC that legitimate CAPTCHA checks do not require pressing Win+R or manually running commands. Consider using a standard, non-administrator Windows account for everyday use and keeping Windows, browsers, and security software updated.
This type of fake verification commonly delivers an information stealer. It may search browsers for saved passwords, session cookies, autofill data, cryptocurrency wallet files, and other sensitive information. Stolen session cookies can sometimes let attackers access accounts without immediately needing the password, so affected passwords and active sessions may need to be reset.
If anyone did run it, disconnect the computer from the internet, run a thorough scan with reputable security tools, and change important passwords from a different, clean device. Sign out of all active sessions and enable multifactor authentication where possible. Don’t test the command on another machine unless you’re working in a properly isolated malware-analysis environment.

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