Information can be found at: http://www.f-secure.com/v-descs/witty.shtml
Also, the original place that talked about this worm (with a packet capture and more information) is:
http://isc.incidents.org/diary.html?date=2004-03-20
You can find a snort rule there.
Note that this worm is only 909 bytes, but as a friend of mine mentioned, slammer was only 376.
Gadi Evron.
