It has now been shown that 17 is the least random number! Figure that one out. OK.. so I admit it, I'm messing with you contextually here. This website talks about two interesting reports (Here is one example) that notes that human beings are very poor at picking random numbers. After sampling 347 (not nearly enough I know) people, the most commonly picked number is "17" with second place being "7". The website also shows that more people will pick an odd number than an even number. People also tend toward prime numbers. Isn't it funny how the human brain is wired?

So what does this have to do with security? Passwords and PINS. We all know that passwords and PINS are typically easy to guess and/or brute force. This might actually be a useful piece of knowledge when attempting to automate PIN and password guessing attacks. It's also demonstrates a possible way to automate attacking systems that allow users to choose "reminder values" for when they forget their password.