Here is the real problem with computers.
We can theorize all day about the ways a system could be taken down, or made secure.
And then one day it's compromised because of something no one ever thought of.
I crashed into a secure system by accident once simply because I hit \\ instead of backspace backspace, then pushed enter without seeing my mistake.
Next thing I know I'm looking at the secure database of all the users private information. Addresses phone numbers everything....
This happened as I was attempting to join one of those free internet companies back in the 90s. I called about their error, and they corrected it right away, but their business never really took off, and it was totally gone within 2 years.
Anyhow you see my point. It's almost impossible to test every possible data entry error that a user could make into a database. If I was a black hat guy I could have compromised the accounts of a whole lot of people!
But this s*** happens every once in a while and they're not always nice guys that stumble into these things.
That was, in fact the third time that such a thing as ever happened in my life, where I inadvertently hacked a system.
Which is not to say that I've never hacked anything on purpose. I have hacked plenty of games that I found boring and decided I wanted to see the end of.
Sometimes I had help with the hacking and sometimes I did not. Often the solution was more simple than you folks could believe.
But those were kid games & not complex Financial systems, yet I don't for a moment hold the illusion that such systems are truly secure.
A famous musician once told the Press, " I am not a virtuoso. A virtuoso can play anything. I can only play what I know."
It's hard to play what you don't know the tempo of and it's hard to secure against threats that you don't know the nature of.