Huge increase in spam from Office 365 domains.

Over the past months I’ve seen a steady increase in spam from email addresses via Microsoft Office 365 servers.

It looks to me that spammers are now signing up trial accounts on Office365 and using the non-verified domains to send their spam.


I’m not sure what the sign up procedure is for email services and how they validate accounts but it clearly isn’t working :(



Received: from
 ( []) by (8.13.8/8.13.8) with ESMTP id rA1BgqhT026375 for
 <>; Fri, 1 Nov 2013 11:42:53 GMT
Received: from [] ( by ( with Microsoft SMTP
 Server (TLS) id 15.0.800.7; Fri, 1 Nov 2013 11:42:58 +0000
Content-Type: multipart/alternative; boundary="===============1741518401=="
MIME-Version: 1.0
To: Recipients <>
From: <>
Date: Fri, 1 Nov 2013 17:12:51 +0530
Reply-To: <>
Message-ID: <>
X-Originating-IP: []
X-ClientProxiedBy: ( To (
X-Forefront-PRVS: 00179089FD
X-Forefront-Antispam-Report: SFV:SPM;SFS:(199002)(189002)(81542001)(85306002)(84326002)(59766001)(77982001)(81956001)(81686001)(43066001)(71186001)(5406001)(74366001)(512934002)(81342001)(83072001)(81816001)(74876001)(76482001)(66066001)(69226001)(31686002)(63696002)(4396001)(76176001)(33646001)(83322001)(80976001)(54316002)(74662001)(74502001)(47446002)(56776001)(47736001)(47976001)(50986001)(49866001)(564344003)(46102001)(76786001)(80022001)(74706001)(65816001)(76796001)(79102001)(51856001)(56816003)(74316001)(77096001)(76576001)(54356001)(25636003)(87266001)(42186004)(84722001);DIR:OUT;SFP:1501;SCL:5;SRVR:HKNPR03MB033;H:[];CLIP:;FPR:;RD:InfoNoRecords;A:0;MX:1;LANG:en;
X-Greylist: Recipient e-mail whitelisted, not delayed by milter-greylist-2.0.2 ( []); Fri, 01 Nov 2013 11:42:53 +0000 (GMT)
X-Antivirus: avast! (VPS 131031-1, 31/10/2013), Inbound message
X-Antivirus-Status: Clean


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1 Response to Huge increase in spam from Office 365 domains.

  1. Mike W. says:

    Probably safe to have a rule blocking anything with “” in it. If a company has signed up for O365, but can’t bother to get their own domain, it’s not worth dealing with them!

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