This reminds me of an article on wired[1] where someone hacked into hosts that were hooked into legacy X.25 networks. And just like mainframes and COBOL, there

This reminds me of an article on wired[1] where someone hacked into hosts that were hooked into legacy X.25 networks. And just like mainframes and COBOL, there are not very many engineers who understand X.25 networks today, and hence had a very relaxed security posture. [1] https://www.wired.com/2016/05/maksym-igor-popov-fbi/ https://www.wired.com/2016/05/maksym-igor-popov-fbi/