I use Webroot SecureAnywhere as my antivirus and it detected an unknown mod for Street Legal Racing Redline as a threat. It just said that the Steam Workshop had a virus, and I do not know which mod had the virus. However, Webroot detected mods for other games as safe. But I am worried that that was a false negative and that someone could hack into the mod and add a virus. However, I am not sure if the mod that contained a virus was a real threat, or a false negative. The Steam Support website says that antiviruses interfere with Steam. But who knows what viruses could be out there?