~20 years ago it was still not rare for someone to email his friends a little Flash game or greeting card wrapped in an .EXE so they could run it straight from Outlook. In retrospective, those were crazy times. We knew about viruses from the time of MS-DOS, and still happily emailed executables that not even Hotmail or Google bothered to block.
All our network traffic was unencrypted, which enabled all kinds of shenanigans until the security culture seeped into corporations and the public.
When stories talk about time travelers that hijack old technology instantly, it makes complete sense. Someone with modern hardware, software, and knowledge could completely break most technology back then. They better not forget their modem, though.
