Three hundred and seventy-six bytes.

That's all there was to "Slammer," 376 bytes. When you think about it, it's amazing that a piece of code could have wreaked such havoc on the Internet and caused such widespread system failure -- at about the size of two paragraphs of this column.

What is even more amazing is that this worm was a success in the first place. Many layers of our security model had to fail for Slammer, or "Sapphire" as eEye dubbed it, to make it as far as it did: Not only did there need to be a large installation of un-patched SQL/MSDE boxes in use, but they also needed to be reachable over the Net on UDP 1434.

As usually, the worm starts and ends with the unpatched available system. Every major worm we have seen exploited a known vulnerability in a service, be it Nimda, Slapper, Slammer or Code Red. Code Red was supposed to be a wake-up call, but it is obvious that many hit "snooze," rolled over, and went back to sleep.

And this time, it cost us.

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