Malware (specifically adware) browser extensions or malware on computer. Edit: I mentioned malware on ISP, but I guess Google has their TLS in order so the ISP

Malware (specifically adware) browser extensions or malware on computer. Edit: I mentioned malware on ISP, but I guess Google has their TLS in order so the ISP shouldn't see or be able to mess with the content like they did before. Not necessarily saying this happened on the user end though, I just outlined how it could happen.