Scareware is malware that exploits users’ fear of online threats. It presents alarming pop-up messages claiming the device is infected, then pressures the user into purchasing fake “security software” — which is itself malicious or completely useless.

“CRITICAL ERROR MESSAGE! — REGISTRY DAMAGED AND CORRUPTED.” | “WARNING: YOUR COMPUTER IS VULNERABLE! CLICK HERE TO PROTECT YOURSELF!”

How Scareware Works

1. A user visits a legitimate site but is redirected to a malicious page that runs a fake security scan.
2. The fake scan reports malware and generates urgent pop-ups urging software purchase.
3. The purchased “fix” is either useless or actual malware installed on the system.

Scareware infections reached nearly 8 million in the second half of 2008 — a 48% increase from the prior six months (Microsoft Security Intelligence Report, 2009).

Warning Signs

• Unsolicited ads promising to delete viruses, improve performance, or clean the registry.
• Pop-ups claiming your antivirus is out-of-date and your machine is in immediate danger.
• Unfamiliar websites initiating security scans without user action.
• Pressure to download free “security scanners.”

Prevention Guidance

• Shut down the browser immediately — do NOT click “No,” “Cancel,” or ✕. Use Task Manager (Ctrl+Alt+Del → End Task).
• Search the software name in a search engine before downloading anything.
• Legitimate antivirus vendors never use browser ads to alert users about infections.
• Always update antivirus through the application’s own control panel, never through pop-up prompts.