Squid sending UDP to port 7 of a remote server? Possible?

I got a nasty-gram from Citizens bank yesterday, when two UDP packets
went to the "echo" port from our proxy server. After looking through
logfiles, there were accesses to www.citizensonline.com (the machine
that recieved the packets) moments after the first UDP packet was
sent, and then the final access a couple of minutes before the second
packet.

Is it possible that these UDP packets could have originated from Squid
in some way? The machine itself is very well-buttoned down, and
inaccessable for login to just about anywhere except a couple of
machines, and there's no evidence of any unusual activity. Thanks for
any suggestions!

        -Mike Pelletier.

--
 "[It will] be very hard to increase browser share on the merits of
  [Internet Explorer] alone.  It will be more important to leverage
  the OS asset to make people use IE instead of Navigator."
			-- Christian Wildfeuer, a Microsoft Manager