Huge Amount of SPAM

[MorfiusX]

I have a client who is recieving a HUGE amount of spam. I am trying to figure out what is going on. Looking at the firewall, it shows they have sent out 15K+ emails in the last 24 hours. This company only has 50 users and none of them work on Saturday. Here is a graph of the last 24 hours:



I have ran an open relay check which turned out OK. I am running a virus scan as we speak. They are using Exchange 2003 on Windows 2003 with Antigen 9.0 and Antigen Spam Manager.

I have found anything wrong per se, but something doesn't seem right with this picture. Any ideas?

Also, the firewall is new. So, I don't know if the 15k message are rejection notices or not. I just trying to figure out what is going on.

 

[MorfiusX]

I may have found my problem. I believe Antigen was sending out a notification to the sender of every spam that was recieve. This in turn was rejected due to a spoofed from address. I think basically I was getting two or three messages generated for every "legitimate" spam I recieved.