Security Incidents: Fragmented UDP and Multicast Addresses

["Chris Martin" <chris () mainstreethost com>]

Hello list,
Today at work we found some very strange behavior on one of our servers.
This machine was spitting out several thousand fragmented UDP packets to
an IP multicast address.
The rate of packet sending was quite high, using ethereal for about 10
minutes showed that of approximately 75,000 packets, almost 70,000 of
them where these fragmented UDP packets.  They were being sent to a
239.192.*.* which according to RFC 3171 is an Administratively Scoped
Block of IPv4 Multicast.

This really has us scratching our heads.  I was wondering if anyone here
had seen this kind of behavior before, or had any ideas as to what it
could possibly be?

Thanks,
Christopher S Martin