03-07-2018 08:17 AM - edited 03-07-2018 08:55 AM
03-07-2018 08:17 AM - edited 03-07-2018 08:55 AM
Our CFO has Multi-Factor authentication set up and working. Someone tried to send an email on his behalf to a non-existent email address, so he received the bounce back in his inbox. The original email was never in his Sent box, but how is it possible that someone (a hacker I presume) could send email on his behalf, through Office365, without authenticating as him?
Here are the message headers, I replaced the sender (our CFO) with YYYYY and the recipient (a non-existent mailbox) with XXXXX
Original Message Headers Received: from BN3PR11CA0018.namprd11.prod.outlook.com (2a01:111:e400:51e4::28) by SN1PR11MB0574.namprd11.prod.outlook.com (2a01:111:e400:530f::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P256) id 15.20.548.13; Wed, 7 Mar 2018 15:43:47 +0000 Received: from DM3NAM05FT022.eop-nam05.prod.protection.outlook.com (2a01:111:f400:7e51::208) by BN3PR11CA0018.outlook.office365.com (2a01:111:e400:51e4::28) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.567.14 via Frontend Transport; Wed, 7 Mar 2018 15:43:47 +0000 Authentication-Results: spf=neutral (sender IP is 220.127.116.11) smtp.mailfrom=risebakingcompany.com; risebakingcompany.com; dkim=pass (signature was verified) header.d=messagingengine.com;risebakingcompany.com; dmarc=none action=none header.from=risebakingcompany.com; Received-SPF: Neutral (protection.outlook.com: 18.104.22.168 is neither permitted nor denied by domain of risebakingcompany.com) Received: from new1-smtp.messagingengine.com (22.214.171.124) by DM3NAM05FT022.mail.protection.outlook.com (10.152.98.132) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.548.7 via Frontend Transport; Wed, 7 Mar 2018 15:43:46 +0000 Received: from compute7.internal (compute7.nyi.internal [10.202.2.47]) by mailnew.nyi.internal (Postfix) with ESMTP id 573EE10F1 for <XXXXX@risebakingcompany.com>; Wed, 7 Mar 2018 10:43:46 -0500 (EST) Received: from frontend1 ([10.202.2.160]) by compute7.internal (MEProxy); Wed, 07 Mar 2018 10:43:46 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-transfer-encoding:content-type :date:from:message-id:mime-version:reply-to:subject:to :x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=J5yc94p8OcoMielqo weJHr1/JS5dWOFLsW5ZI0n+giI=; b=Sros9ppkL1hz/XZGS/A7gcjWZy4Q1fdOB 376jMEyio6zHl6jbNQdux/qAwsnrtTXqJr3IJqkjpOefkZ+hCO9buu7z+X5CEOZo FdwSzzmwQHgkZ6D+XMd/rUXXG0votMRAOUZErS1DdUTm64YZu6o+74Ti/I+DNPt/ HCHaK5JxzYtIhk6Dydy0kXWL4IYx+zKoJJ+h90brysy6hk9l1L+FK4Lo1QjEgk4G t1w2MvwgjPaBRibLVwoZ5ic9DyYtXtoQdOEF4xNfvC7wSE4apAF2RqJZCc+I+YEQ lRVnPrD2Mt5s5WTgpIumqC2c14bJFNHz9PGzRn+sckLvLIroqZ9xA== X-ME-Sender: <xms:sgigWt3l2Il5qJP0vi8x-g3P3mmsCsFjIkz3MPBYz2AwZZnY_PnjZA> Received: from Ms-MacBook.local (unknown [126.96.36.199]) by mail.messagingengine.com (Postfix) with ESMTPA id 9D2167E660 for <XXXXX@risebakingcompany.com>; Wed, 7 Mar 2018 10:43:45 -0500 (EST) Reply-To: YYYYY@mobiledevice.mobi To: XXXXX@risebakingcompany.com From: Chris YYYYY <YYYYY@risebakingcompany.com> Subject: Kindly get back Message-ID: <firstname.lastname@example.org> Date: Wed, 7 Mar 2018 10:43:44 -0500 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Return-Path: YYYYY@risebakingcompany.com X-EOPAttributedMessage: 0 X-EOPTenantAttributedMessage: 9c9ca00d-d89b-441e-a989-1ae7f6387804:0 X-Forefront-Antispam-Report: CIP:188.8.131.52;IPV:NLI;CTRY:US;EFV:NLI; X-Microsoft-Exchange-Diagnostics: 1;DM3NAM05FT022;1:22KTfsIJsrHtk/9hXI7qkXbLBstTxAbLpPufCoqKHWGJ4egiyN9wLIV2Evy2BOE4ZyF7IR3XeGyx94qwyUTSJ4yzyLM4x1stQhhuaziR6t+CkNW6DCOra22VCBBlc7/L X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: c30401f0-1aeb-4fd8-d598-08d58442372f X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:(7020095)(5600026)(4604075)(4605076)(1401096)(8001031)(1405069)(71702078);SRVR:SN1PR11MB0574; X-Microsoft-Exchange-Diagnostics: 1;SN1PR11MB0574;3:JnjkmfARjIFKfRcfYH04lGJThsNTuDO2UXaa3HxjtBYDGHgp2u8EIwEVE7vdskPBMjMNYbTuTsGpy+Gm/28pnLF5t2J9NubNlIao4u43MQ2Z3QvkUNX7/iXeXqZ/3iuDYibXCqyQgg+IqpUoXisn88d9eJY2ScT4OZ2N6QTgpMyiwE2/Mcx5GrDV66e94aIDc79i1zPw9+NA89HB0sntt8lxyC6ksaNFnNrFwuMyVF+fl+U/sqExp1wlZjrxUpNrEpmMbDPMjFQE8zqRLhGwz4XAiWOJwM+GyC5C6J0mpxt9cAbW83sRkGUFlbgSz3L2xQKMMGWLkMkD9ZFXd0WgcOnLHphjkWihyv5ZYZjM014=;25:t4rn8dm6J9zqIzoLygCSGsmXepkYJWl+eJTmJ57mzPdsJaBI5uVSYNRp88A5rH0OoCnKcK5iuclzKOVzyAJZ54mA8HUBHtQ+DQVRr5aXpHGy85COQ3XFWBkeVlqedreVIqpK6ubd83vzJUc/7axsFWityzAudHxnqL9QXe4jJxAy1okbCJpAFK65Quk+RQfB9eJbqlq5RIH921S8YjhxswZ65/sok4+gTFmJ31rI0Q3eQpzUjcB1TLExVCw2biqGvKXyAvYxfOuBl7vLYDorbRBUePkzbGJlPf7O89HBeO5C08pQ9Bln0fwqTklt7uC68Vlk0n4UYG42ZoSPEyacow== X-MS-TrafficTypeDiagnostic: SN1PR11MB0574:
03-07-2018 12:05 PM - edited 03-07-2018 12:07 PM
Looks like a typical spoof attempt to me. Anyone can send anything as anyone on the internet when it comes to SMTP. I could pop out to my SMTP server and send an e-mail as YYYY@risebakingcompany.com if I wanted to to anyone I wanted. If they aren't using DKIM or SPF etc. it could very well get through, but in this case it was blocked and returned whom the message was set as the from address.
03-07-2018 12:08 PM
This is hard for me to believe, simply because I have devices on my network that I have set up to send alerts via SMTP, and if I do not authenticate as the same email as the sender it fails to send the email. SMTP via O365 seems to be very picky on what it accepts, simply because SMTP use to be so open and allow for anyone to send anything. I thought that was fixed now.
03-07-2018 12:24 PM
So you are saying that their servers allowed them to send email from our O365 domain to us, using their SMTP servers, not ours? If so, wouldn't it show the email address they used to authenticate against their SMTP server, or they just sent it anonymously with no authentication?
03-07-2018 12:27 PM
03-07-2018 12:30 PM
oh, we got a bounce back because the TO email address does not exist, not because it was blocked as spam. The email address they were sending to was not valid. If it would have been, the email would have been delivered and we would have never known about it.