Spam from (forged) whitelist domain

[Andy Alsup]

I see a nontirvial volume of Spam that gets through to users using
forged headers with my domain as the from.  These are typically to:
user at mydomain from: user at mydomain

My domain is whitelisted, so when a forged header comes along,  I get a
spam score that would have dealt with the spam, but it is whitelisted,
so delivered anyway.

Is there a way to deal with this?

Thanks.