Empty spam messages?

[Johannes Klug]

Hello bogofilterers,
I have been receiving a couple of empty spam messages lately.
They only contain headers, but no Subject oder Body part.
An example is attached. (zipped, so it does not spoil databases ...)

I was just wondering what these messages are.
Have the bodies been removed by some spam-filter on their way?
Or did the spammers just misconfigure their software?

Greets,
Johannes
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