Assuming a character had the correct physical access, how difficult would you make the astrogation, computers and mechanics checks to introduce a flaw into a navicomputer's astrogation data such that it would fly into a black hole, sun, or other large mass? What about the central computer on a mliitary network from which all ships would receive their updated astrogation charts?
Contextually, in a campaign I'm playing in, we have a major opposition group that is building capital ships by the hundreds from literally dozens of shipyards. Rather than trying to capture those shipyards or otherwise disrupt/disable the supply, I was thinking of introducing a flaw in their navigation data such that they would have a (low) chance to run into planets or somesuch. This way we wouldn't have to worry so much about the supply. Just force them to jump around the galaxy and eventually they'll run into something.
So... Thoughts on the difficulty of such a plan?