A few more details: I don't have any cracked software installed. I also keep browser extensions to a minimum: AdBlock, EFF extensions, Mozilla approved extensi

A few more details: I don't have any cracked software installed. I also keep browser extensions to a minimum: AdBlock, EFF extensions, Mozilla approved extensions and that's pretty much it. I installed Little Snitch again and I don't see anything unusual in the network activity. My security settings only allow "Mac App Store and identified developers" applications to run. My router is an Airport Express. I will reset it, change the username and password, but there's not much I can do with it. Many years ago when I used Windows I had a few antivirus and other software that I relied on to check my computer for virus, malware etc. I was wondering if there's anything similar that you trust for OS X.