Security Tool, otherwise known as SecurityTool, is a rogue anti-spyware program from the same family as System Security. This program is promoted via the use of Trojans and web pop-ups. When the program is installed it will be configured to start automatically when you login to your computer. If you attempt to remove these infections, though, it will not allow it until you first purchase the program. The scan results are a scam and the infected files it states are on your computer are actually legitimate Windows files. Thankfully, we have a way of bypassing these restrictions so you can fix your computer without paying the ransom.
Source: https://www.bleepingcomputer.com/virus-removal/remove-security-tool