With patching, the only certainty is that CISOs will bear the costs of bringing order to the intractable. In this penny-pinching era, other C-level executives are bound to ask the CISO why this is necessary, at which point someone's gonna have some 'splaining to do.

The Learned Art

Patching is, by most accounts, as old as software itself. Unique among engineered artifacts, software is not beholden to the laws of physics in that it can endure fundamental change relatively easily even after it's been "built." Automobile engines don't take to piston redesigns post-manufacture nearly so well.

This unique element of software has contributed to (though is not solely responsible for) the software engineering culture, which generally regards quality and security as obstacles. An adage among programmers suggests that when it comes to software, you can pick only two of three: speed to market, number of features, level of quality. Programmer's egos are wrapped up in the first two; rarely do they pick the third (since, of course, software is so easily repaired later, by someone else).

Such an approach has never been more feckless. Software today is massive (Windows XP contains 45 million lines of code) and the rate of sloppy coding (10 to 20 errors per 1,000 lines of code) has led to thousands of vulnerabilities. CERT published 4,200 new vulnerabilities last year--that's 3,000 more than it published three years ago. Meanwhile, software continues to find itself running evermore critical business functions, where its failure carries profound implications. In other words, right when quality should be getting better, it's getting exponentially worse.

Stitching patches into these complex systems, which sit within labyrinthine networks of similarly complex systems, makes it impossible to know if a patch will solve the problem it's meant to without creating unintended consequences. One patch, for example, worked fine for everyone--except the unlucky users who happened to have a certain Compaq system connected to a certain RAID array without certain updated drivers. In which case the patch knocked out the storage array.