Rogue security software, also known as scareware, is software that appears to be beneficial from a security perspective but provides limited or no security, generates erroneous or misleading alerts, or attempts to lure users into participating in fraudulent transactions.

Rogue security software designers create legitimate looking pop-up windows that advertise security update software. These windows might appear on your screen while you surf the Web.

The "updates" or "alerts" in the pop-up windows call for you to take some sort of action, such as clicking to install the software, accept recommended updates, or remove unwanted viruses or spyware. When you click, the rogue security software downloads to your computer.

Rogue security software might also appear in the list of search results when you are searching for trustworthy antispyware software, so it is important to protect your computer.

Rogue security software might report a virus, even though your computer is actually clean. The software might also fail to report viruses when your computer is infected. Inversely, sometimes, when you download rogue security software, it will install a virus or other malicious software on your computer so that the software has something to detect.

Some rogue security software might also.

• Lure you into a fraudulent transaction (for example, upgrading to a non-existent paid version of a program).
• Use social engineering to steal your personal information.
• Install malware that can go undetected as it steals your data.
• Launch pop-up windows with false or misleading alerts.
• Slow your computer or corrupt files.
• Disable Windows updates or disable updates to legitimate antivirus software.
• Prevent you from visiting antivirus vendor Web sites.

Rogue security software might also attempt to spoof the Microsoft security update process.  Here's an example of rogue security software that's disguised as a Microsoft alert but that does not come from Microsoft.

The following are screen captures of Rogue Security software

Example of Windows Security Alert