I'm currently seeing on two completely independent mail platforms incoming mails from newsletter4-bounces@moneycab.ws, which seem to be out-of-office replies sent back to the mailing list and redistributed again... you get the idea ;)

I suggest you check your smtp logs whether you or your customers are also victims of this sender, and act accordingly if you are.

from=newsletter4-bounces@moneycab.ws, relay=ml05.ispgateway.de [80.67.18.71]

(I wouldn't assume the relay to be constant though). At least one mailing list currently being part of this problem is:

"Swiss Leadership Forum - Newsletter vom 30.04.2012"

nice to know Swiss leadership doesn't know how to deal with buggy exchange out of office replies :)

Cheers, Markus