Possible Exchange 5.5 Server DoS

<<exerror.zip>>
This happend early this morning on one of our mailservers running Exchange
5.5 on WinNT4 OP5.
Suddenly the Information Store (STORE.EXE) crashed with a strange error
saying something in the way of
"Error while processing an email message", restarting both the server and
all of Exchange's components
has no effect at all. The only way of solving this problem as I discovered
is to shut down all Exchange Services
and Totally remove the content of the IMCDATA directory containing the mail
queues and then restart exchange.

It seems that the attachment line is the problem, by removing the attachment
and sending the mail nothing happens.

Anyone know of some more information about this "DoS" attack or how it can
be prevented,
I have not seen any off things in the mail that would bring an Exchange
server to a stop.

This message has been sent to Microsoft who has not yet given any answer.

Regards,

[email protected]
system administrator / computer technician

wallingatan 11, 111 60 Stockholm
tel +46 8 412 41 19, fax +46 8 412 41 79
mob +46 733 73 33 19 www.deo.com