Spam from people I know

[Drsolly <drsollyp () drsolly com>]

This started a couple of months ago, but it's getting bigger in volume.

I get a spam, no subject, sent to maybe half a dozen people. But it comes 
from someone I'm in email contact with (i.e., I've sent them an email, 
maybe they've sent me one).

What's the malware that causes this, and what will detect it? 

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