Scratch has been hacked and a virus is going around. Here is what we know. The virus only affects you if you look inside a project and go into a costume editor. SO TO PLAY IT SAFE, DO NOT LOOK INSIDE ANY PROJECTS UNTIL GIVEN THE ALL CLEAR
The ‘virus’ actually explained So, it's actually not a virus, but a vulnerability/exploit that has affected many Scratchers. It works by going into the project editor (or clicking ‘see inside’) and then going to the costume/backdrop editor. When you open it, the costumes can actually do Arbitrary Code Excecution, which is a way that code can be excecuted. In the desktop/offline editors, it's even worse because then they can run malicious shell programs and steal data from you! And this is not a theoretical possibility, it has already affected multiple Scratchers. What it can do It can delete and/or hack all projects, change the description of the victim's profile, comments things on the victim's profile without their concent and run malware (only on desktop/offline editors).