Steve Jobs is using Apple Software Update to slip his Safari browser onto Windows machines. And Mozilla CEO John Lilly is peeved.

Presumably, Lilly is peeved because Safari browsers on Windows machines would eat into the market share of Mozilla's very own Firefox browser. But Lilly says he's peeved for different reasons. He says he's peeved because Steve Jobs' little Software Update trick undermines the security of the entire internet.

"What Apple is doing now with their Apple Software Update on Windows is wrong," Lilly writes on his personal blog. "It undermines the trust relationship great companies have with their customers, and that’s bad - not just for Apple, but for the security of the whole Web."

Steve Jobs and company unveiled Safari 3.1 on Tuesday, and to celebrate, they began offering the new browser to Windows users via Apple Software Update - that clever little tool that alerts you to new Apple software with a nothing-less-than-conspicuous pop-up window.

On Windows machines, Apple Software Update is automatically installed alongside iTunes and Quicktime. So you can bet that Safari has been offered to many millions of folks over the past week.

"Safari for Windows is the fastest and easiest-to-use web browser for the PC," reads the pop-up window that pops up on Windows PCs. "It displays web pages faster than any other browser and is filled with innovative features - all delivered in an efficient and elegant user interface."

This should come as no surprise. When Steve Jobs debuted Safari for Windows back in June, ZDNet's Mary Jo Foley points out, he said quite plainly that he would piggyback the browser on iTunes. "We know how to reach these (Windows) customers,” Jobs said.

But John Lilly is still peeved. He points out that when Apple Software Update offers you Safari, it does more than just offer. "The problem here is that it lists Safari for getting an update - and has the 'Install' box checked by default - even if you haven’t ever installed Safari on your PC."

And he insists that this sort of behavior could destroy security as we know it. "By and large, all software makers are trying to get users to trust us on updates, and so the likely behavior here is for users to just click 'Install 2 items,' which means that they’ve now installed a completely new piece of software, quite possibly completely unintentionally. Apple has made it incredibly easy — the default, even — for users to install ride along software that they didn’t ask for, and maybe didn’t want. This is wrong, and borders on malware distribution practices.

"It’s wrong because it undermines the trust that we’re all trying to build with users. Because it means that an update isn’t just an update, but is maybe something more. Because it ultimately undermines the safety of users on the web by eroding that relationship. It’s a bad practice and should stop."

Of course, it could also undermine FireFox's market share. And if it does, ZDNet's Larry Dignan argues, the millions that Google dumps onto Mozilla may get dumped onto Apple instead. Like Mozilla, Apple has agreed to make Google its browser's default search engine.

But in a follow-up blog post, Lilly says none of this is on his mind. "Lest anyone be at all confused about my motives in writing my recent post about Apple Software Update, I’ll say this unequivocally: it isn’t about competition. [I wrote what I meant in my post - there’s no subtext at all - it’s all on the page, so I won’t rehash it here.]

"To the contrary: competition is good - necessary, actually. Competition - or, more the point, the ability of people to choose what tools and services they use - is essential, and without it nothing gets better." ®