Complexity is the enemy of security

There's been such a flurry of patches lately I've given up updating. They come out so quickly there's not time to see which ones are stable and which introduce new problems. I hope we get a quiet week to catch up. In the meantime, I was struck by this statement:

Slashdot | Zero Day Hole In Google Desktop:

... With knowledge of the Google Desktop security model (a combination of one-time tokens, iFrames and JavaScript), hacker Robert Hansen figured out a way to sit between a target launching a Google search query and manipulate the search results to take control of other programs on the desktop. From the article: 'This should drive home the point that deep integration between the desktop and the web is not a good idea, without tremendous thought put into the security model."...

It's very hard to create security within a single architecture. When you create relationships between disparate architectures, such as an XP environment and a web services model, security becomes very difficult. There are too many affordances, too many gaps that can't be filled, too many emergent behaviors....