Answering some repeated questions about the situation below:
How can I check that I've been affected? Download the overwolf detector (https://github.com/overwolf/detection-tool/releases) and run it, it will tell you if you have any files that were created by the virus.
I'm infected, what do I do? Depending on the timeframe you were infected, its likely that your system may or may not be fully compromised. The safest assumption is to assume it is, and you should completely reinstall windows fresh. You may save files that are NOT .jar (so do NOT save any minecraft mods), and you MUST change all your passwords. This is because the virus steals discord passwords, minecraft passwords, passwords saved on your browser, and your clipboard history.
Is it safe to play my modpack if I downloaded it a long time ago? Download the overwolf detector above and run it. If you've played the modpack recently and the detector does not detect files, you're very likely fine. If it does, you may be compromised and should follow the steps above.
Is it safe to download mods from curseforge? For the meantime, no. We don't recommend installing ANYTHING from curseforge, because it is possible that malware mods are still listed (curseforge is actively working to de-list them be patient). Do not update anything you have on your PC either. You may continue to play your modpacks AFTER you run the overwolf detector and ensure that nothings compromised on your system.
I dont use curseforge/overwolf, do I have to install them to use this program? No, you do not need either curseforge or overwolf to run the detector. It will work with any launcher that you have installed, as it doesn't need anything other than java.
Does this virus affect Windows/Linux/MacOS? This virus ONLY affects windows and linux. We believe that linux had minimal effect due to the virus being poorly coded and wouldn't work without priviledge escalation. Windows on the other hand is very badly affected. MacOS is NOT affected by this virus.
Which one do I run, Overwolf or Neko? Whats stage 0, whats stage 1-3? Stage 0 is the FIRST step of the virus, and detected by the Overwolf Detector linked above. If this does not exist on your PC, or if overwolf detector says you are safe, then you do NOT need to worry about the virus. If it says you are compromised, or malware was found, then its likely your virus entered stages 1-3. At this point, you should follow the steps above to completely clean your PC and reset your passwords. You can alternatively run neko detector to remove the infected jars, but you STILL MUST CHANGE YOUR PASSWORDS.
After running the detector, can I download modpacks? NO!! Curseforge still has mods/modpacks with the malware, avoid installing ANYTHING for the time being. Once we give you the all-clear, hopefully by tomorrow, you may continue to install mods and modpacks. Until then, do NOT INSTALL ANYTHING. DO NOT UPDATE MODPACKS EITHER.
Am I infected? Do I need to throw away my PC? WHAT DO I DO?!?!1 don't panic, install the overwolf detector and run it. if it does not detect anything, you are SAFE. you do NOT need to do anything else.