How do I stop impersonated emails?

[Uhl-Services]

Good day,

Received: from [45.112.69.32] (port=15889 helo=node-45-112-69-32.alliancebroadband.in)
by panel.uhlhosting.ch with esmtp (Exim 4.87)
(envelope-from <ganja@highacid.com>)
id 1bIyUG-0009Hq-Fu
for ganja@highacid.com; Fri, 01 Jul 2016 15:28:04 +0200
From: <ganja@highacid.com>
To: <ganja@highacid.com>
Date: 1 Jul 2016 22:28:20 +0400
MIME-Version: 1.0
Subject: We offer new vacancy
Message-ID: <5776BD10.8992.92D9A2@ganja.highacid.com>
Priority: normal
X-mailer: Pegasus Mail for Windows (4.52)
Content-type: multipart/alternative; boundary="Alt-Boundary-35690.2994386"

They are sending emails on name of my server and my domains. How can I teach SpamAssasin to avoid these, yet in same time not to have a bad score on my domains. None of my IPS are blacklisted or having a bad reputation. Is there any workaround to stop eliminate impersonated emails?

http://prntscr.com/bstlfj

Thank you,
Cosmin

[Sergio]

The first thing to do is to enale SPF and DKIM on each of your domains, that will help exim to block that type of spam.