Yes, I'm sure you could pretty easily write said program. Then the people who did this would obfuscate their code and you could probably then detect that...and

Yes, I'm sure you could pretty easily write said program. Then the people who did this would obfuscate their code and you could probably then detect that...and the game whack-a-mole will continue. Eventually as this cycle continues you will end up with something that looks a lot like today's anti-virus programs, (aka a pattern recognition engine...). It's the (theoretical?) software that can detect these types of attacks before or as they are happening that is of interest to lots of people now a days.