New virus spreading around steam

Currently two people have sent me a message to download a "screenshot", but instead of it being a .jpg(.png etc.) it was a .scr. This extension was unkown to me, and neither of my friends sent this message. It was sent from there computer and there steam account. So everyone make sure you do not go to any link from a friend unless informed about the content first. If you have accidently oppened the file ending in .scr make sure to download a anti-malware program(https://www.malwarebytes.org/mwb-download/) then scan with it, and change your passwords. Make sure to invite as many people as possible to this group, so no more people are affected by this.

More on this: Ive learned that this file is used for phising. This was mainly used for people to steal the trade able items. This is a form of malware, and can be used for more then just stealing trade items.

Source: https://blog.malwarebytes.org/fraud-scam/2014/11/rogue-scr-file-links-circulating-in-steam-chat/