Botnet of course.
Any X11 and X13 coins are botnet friendly.
First repacks of Watch Dogs had hidden miner.
Do you know how many stupid people are downloading everything without check?
I'm sure our wallets are botnet free - they are frequently checked and actualized if it is needed. I may give you 100% guarantee our wallets are malware free.

I'm talking not about wallets. Infected code is mostly on torrents with popular repacks of games or software like photoshop etc.