Why PSTN Conferencing Dynamic Conference IDs are so important

Microsoft announced on Friday, August 12th that Dynamic Conference IDs are coming September 1st to Office 365 E5 PSTN Conferencing.

This is an important because it solves a privacy limitation with the current static conference ID’s in service today.

Without dynamic conference IDs, there are no great options to prevent new external callers from interrupting an in-progress meeting (that may be running long). The default ‘out of box’ configuration allows unauthenticated external callers to be admitted into the conference. The option to override this behavior is to change the policy ‘these people don’t have to wait in the lobby’ to “Only me, the meeting organizer.”

However, when that option is selected, the meeting organizer does not receive any pop-up notification to admit PSTN callers who are waiting in the lobby (they just sit there forever). This particular scenario is not directly mentioned in the “Dial-in conferencing known issues” support article. And that is why Dynamic conference IDs will be such a great thing starting September 1st! Note: Any previously scheduled meeting will not automatically have this option, only new scheduled meetings going forward after 9/1 will have this option. Also, any recurring meetings will need to be rescheduled with a new dynamic conference ID to benefit from this privacy feature.

The most useful and controversial changes in Office 365 (Part 2 of 2)

This is part 2. To read part 1, click (here).

In general, Corporate IT Departments want to control the end-user computing experience. Surprises are to be avoided. Pop-ups are anathema to Corporate IT because they result in annoying helpdesk tickets “should I click on this button?” (anyone who has ever served on a helpdesk, God bless them, is rolling their eyes because they know that non-technical people somehow cannot deal with pop-up messages. My favorite: “Should I accept this end-user agreement?” My sarcastic response: “Just click no, we can end this call now and close the ticket.” In all seriousness, surprise pop-up messages that are not communicated first by a trusted source, (“The IT Department”) can cause non-technical end-users to freeze up and panic. Therefore, changes in Office 365 that disrupt the end-user in any way (pop-up messages, etc) are seen as highly controversial (to put it mildly).

Here is a summary of the most controversial changes in Office 365 over the past six months.

  1. The What’s new dialog prompt:

Why is this controversial? First, because this pop-up cannot be suppressed. The ‘What’s New’ dialog box will appear approximately once every 30 days to communicate changes directly to end-users. If the IT Department doesn’t proactively notify end-users about the contents of the pop-up, then this could lead to questions by end-users on whether it is a virus pop-up; many users have been conditioned (wisely) to not click on unfamiliar pop-ups.
Second, because it can advertise features that that IT Department may have disabled, leading to confusion among end-users. For example, if IT has disabled ‘Office 365 Groups’ then do you want a pop-up message to advertise features about it?

  1. The “One-Click Archive” button in Outlook, announced on Feb 25th (here).

Why is this controversial? First, because it generates a pop-up message in Outlook that causes a non-technical person to have to make a decision.

This can lead to helpdesk requests from users seeking advice on what to decide (anyone who disputes this has never worked on a helpdesk before).

Second, because IT has no administrative controls to disable this feature. Why would someone want to disable this? Because if an Enterprise has enabled the Personal Archive feature then this button does not integrate with it, and instead creates a 2nd location to store archived messages. This leads to confusion by the end user on where to look for messages.

  1. OneDrive for iOS App – take data offline -announced May 4th (here)

The OneDrive iOS can now take OneDrive and SharePoint files offline.

Why is this controversial? If you don’t have a Mobile Device Management (MDM) solution such as Intune deployed, how will you wipe the offline files when the employee leaves your organization?

  1. Docs.com – announced August 4th

provides a way for users to Publish Office Documents externally, directly within Word/Excel/PowerPoint, or by browsing to docs.com.

Why is this controversial? If your organization has limited external sharing (for security reasons) then Docs.com allows your users to bypass controls setup by IT/Security. IT Departments who have configured URL filtering to block Google Drive, DropBox and other 3rd party file sharing sites may elect to block Docs.com, since Microsoft currently does not provide any IT controls to disable this feature. For more information click (here).

Second, because your users will be receiving a pop-up notification to advertise this feature. So even if you block docs.com via a URL filter, you cannot suppress the what’s new dialog box.

  1. Clutter is replaced with “Focused Inbox” – announced July 26th (here)

Focused Inbox is essentially a way to quickly filter an inbox to show the most important items, similar to what Clutter promised, but with the advantage of not moving it to a separate folder. This is the same feature that has already been available to the Outlook for iOS (if you are using it).

Why is this controversial? Users will receive a pop-up prompt in Outlook to opt-in to Focused Inbox. After they opt-in, Clutter will no longer move items to the clutter folder. Read this help article for more details on the prompts users will see and how to turn Focused Inbox on and off.

IMHO – Focused Inbox is really a much better way to solve the same problem of decluttering an inbox by simply providing a user a ‘view’ of their inbox. IT should communicate the value of Focused Inbox rather than resisting it or scrambling to disable it. Office 365 admins will have mailbox and tenant level control of the feature to stage the rollout in a manner that works best for their organization. However, I feel this is a good feature that should be left on when it rolls out to first-release subscribers in September.

Honorable Mentions:

Modern UI in SharePoint/OneDrive. Did I miss any controversial changes in the past 6 months? If so, please leave a comment.

Have you been caught off-guard by changes in Office 365? Patriot Consulting offers a monthly subscription service to help IT Departments understand and prepare for upcoming changes in Office 365. Watch a brief video about our service (here) or drop us a note at hello@patriotconsultingtech.com to learn more.

The most useful and controversial changes in Office 365 (Part 1 of 2)

This is the first of a 2-part blog series highlighting the changes in Office 365 in the last 6 months (April 2016 to present).

When it comes to human attitudes toward change, I have found there are three types of people:

  • Those who embrace change
  • Those who resist change
  • Those who are indifferent towards change

This blog post (part 1 of 2) should satisfy those who embrace change, while my second post should intrigue those who resist change. Wait, why not a 3rd post for those who are indifferent towards change? People who are indifferent towards change are probably not reading this blog, as they would have read the title and sighed ‘meh’ before continuing on with their day.

  1. March 18th: Common Attachment Types Filtering for Exchange Online Protection (EOP)

    There is a new configuration setting in EOP feature that provides an easy-to-setup method of filtering out unwanted and potentially malicious attachments by their file types. This feature requires a single click to enable, and can be configured from a list of the file types commonly found to be dangerous. For more information click (here).

  2. April 19th: Office Deployment Tool allows Visio and Project (MSI) to be deployed

    alongside Click-to-Run versions

    This enables IT to deploy the the MSI versions of Visio and Project side-by-side with Office 365 ProPlus click-to-run, as long as they are deployed using the Office Deployment Tool. For more information click (here).

  3. April 14th: OneDrive for Business Next Generation Sync Client (NGSC)

  • The NGSC is 4x faster than the old engine (groove.exe)
  • Includes the highly anticipated ‘Selective Sync’ where users can leave some content in the Cloud and only sync the folders they want
  • Large file limit increased from 2GB to 10GB
  • The sync engine now supports the ‘takeover’ feature, which eliminates the need to re-download all OneDrive content after the NGSC is installed
  • Note: The last feature we are still waiting for is the ability for the NGSC to sync SharePoint document libraries and Office 365 Groups. Until then, Groove.exe must run side-by-side with the NGSC OneDrive.exe

Honorable Mentions:

Flow, Planner, Gigjam, ASM, Bookings, & “Toll Free Numbers in Cloud PBX PSTN Conferencing”

Top 3 reasons I should have adopted Outlook App for iOS a long time ago


1. Send Availability

How often do we get an email like “are you available to meet tomorrow.”  Now, when I reply, I can click a button and select available time slots, and with one more button press, I can quickly send my availability! In this manner, it is actually more efficient than the current Outlook full client!  The closest thing we have to this in the full Outlook  client is the  ‘FindTime’ app in Outlook.



2. Attach Files or Photos while composing email

This is a huge advantage over the native iOS mail client, I still remember when I used an iPhone for the first time and could not find any way to attach a file to an email I was drafting. My friend snickered, “that’s because you have to go to the photo first, then click share, then draft your email.” Hmmm.. okay… I guess but that wasn’t completely obvious to me. So I love the more natural ability to attach a file after I start composing a new email. What I like even more is that it shows me files that have recently been sent to me in email, as well as files I have in my OneDrive (and other storage providers too).


3. Consume RMS protected attachments sent from “RMS sharing app”

One of the main obstacles for adoption of RMS is the lack of support for it on mobile devices. Now, with the Outlook App for iOS, I can open RMS protected content when it is sent from the RMS Sharing App.  What doesn’t work is opening RMS protected email messages although it is apparently supposed to work according to this article (here). Perhaps it is a bug in the latest iOS client since it is listed as being a supported feature.


No Significant Drawbacks

One of the features I liked about the native mail client in iOS is the ability for multiple mail accounts to be added (for example, the ability to quickly check both business and personal email accounts). Happily, this feature works the same in Outlook App for iOS,, and I have not found any other productivity loss.

I have occasionally come across a few instances where the Outlook App for iOS is not detected as a mail client, for example, in Safari it was not one of the default actions when I needed to forward a URL via email. I was able to easily add it to the Safari quick actions, so that wasn’t too difficult. I think there was one other native app that was looking for an account registered as a native account, which I no longer have, so it failed to work. Other than that one drawback, I am very happy with the new productivity enhancements I have gained.

So I have switched from using the native mail client in the iOS to using the Outlook App for iOS and so far I am only wishing I made this switch earlier!

AutoMapping stuck after mailbox migration

After migrating a mailbox to Office 365 Exchange Online, if the mailbox previously had full access permissions prior to the migration, then after the mailbox migration is finished the user may receive lots of authentication prompts. This happens by design since cross-forest permissions are not supported. Mailboxes that require full-access and/or send-as permissions should be migrated together in groups to avoid this issue.

But what happens if someone overlooks this requirement and moves a mailbox without moving the shared mailboxes along with it? This is where it gets very interesting. While it is possible to remove the full-access permission from the on-premises mailbox, that change won’t sync or take any effect and doesn’t solve the issue. Likewise, migrating the mailbox to Office 365 with the permissions removed prior to the shared mailbox migration won’t solve the problem (you might expect the original mailbox to see the newly migrated mailbox and that it no longer has full-access, and that would be enough to remove the AutoMapping feature). However, no, that is not how it works. To remove the auto-mapped shared mailbox, you have to migrate the shared mailbox, add the full access permission, then remove it again. That triggers the delegate’s outlook to remove the shared mailbox from the left navigation in Outlook.

Skype for business Event ID 1047 LS File Transfer Agent

During a deployment at a customer site I ran into a problem with SkypeFB Edge replication.

After adding the Edge to the topology, installing the role on the server and proper certificates, replication was failing with Event ID 1046 and Event ID 1047.

The solution was to add the following registry key:

  1. Open Regedit on the Edge server
  2. Go to HKLMSYSTEMCurrentControlSetControlSecurityProvidersSCHANNEL
  3. Right click and add the DWORD (ClientAuthTrustMode)
  4. Set the value of the DWORD to 2
  5. Restart the server
  6. On the front-end run this command and then wait 2 minutes

Additionally, when working with Microsoft support they also recommended creating these two additional keys:

SendTrustedIssuerList (Value 0) and EnableSessionTicket (Value 2).





There is an interesting troubleshooting article with tracing presented here that could also solve the problem if it was caused by a missing intermediate authority.


And while researching this problem, I came across a very thorough article on this topic that is worth translating into English: http://www.msxfaq.de/signcrypt/win2012tls.htm

Skype for Business Services won’t start

Immediately after installing Skype for Business Server 2015 (Standard Edition) the front-end services would not start.

Tom Rimala’s blog article that suggested there is a problem when the internal Certificate Authority uses MD5 as the signature signing method.

Also, the Microsoft Certificate Requirements says “The default digest, or hash signing, algorithm is RSA.” (no mention of MD5).

I changed the CA Authority’s certificate from MD5 to SHA1. Here is the registry key to change on the Root CA signing information (we changed these three values). Note: the guidance was to change this on the Root and Subordinate but in our case the Root was also the issuing CA, so there was no subordinate to change in our case.


The next step is to restart the Root CA services. Then issue a new Root Certificate. Then copy the new root CA cert to the Skype for Business front-end, and finally re-issued the Front End Cert and OATH cert. Then the services should start up.

There was a false negative warning about Event ID 32174 “Server startup is being delayed because fabric pool manager has not finished initial placement of users.” This is clearly a bogus error because a Front-End server doesn’t have additional servers to place users into.


There was a clue about the Certificate problem because the System Event log contained a ton of Schannel events such as 36888, “A fatal alert was generated and sent to the remote endpoint. This may result in termination of the connection. The TLS protocol defined fatal error code is 40. The Windows SChannel error state is 1205.” And Event ID 36874 “An TLS 1.2 connection request was received from a remote client application, but none of the cipher suites supported by the client application are supported by the server. The SSL connection request has failed.” I am adding these details in the event that a search engine might index these errors to point people to this fix.

Skype for Business Online Delegate Calendar Scheduling

Imagine a scenario where an executive assistant needs to schedule Office 365 Skype for Business Online meetings on behalf of at least two or more executives during the same timeframe.

Without proper training, the assistant may schedule meetings in their own calendar rather than in the calendar of the executives. This can be a major problem if those two meetings need to occur at the same time, because SFB Online does not yet support dynamic meeting ID’s, so you can’t have two meetings scheduled at the same time by the same meeting organizer.

The solution is to schedule the meeting on behalf of the executive, so that they appear as the meeting organizer, and the meeting will use their meeting ID rather than the assistant.

To accomplish this, the executive needs to perform delegation to the assistant in two separate products (Outlook and Skype for Business):

1. Outlook Delegation


2. SFB Delegation


*If you don’t see the Call Forwarding Settings then you don’t have the required license assigned (see license requirements below).


License Requirements (for SFB Online)

The second can be tricky if the minimum required licenses are not assigned. The Executive/Manager needs one of these three license combinations for delegated meetings to work correctly:

1. SFB Online Plan 3

2. SFB Online Plan 3 + Cloud PBX

3. SFB Online Plan 2 + Cloud PBX + PSTN Calling

Then the delegate simply needs to double-click on the boss’s calendar inside outlook to create a new Skype Meeting.



Top 10 tips to bolster enterprise email security


The FBI issued an alert on April 4th that CEO Fraud (a form of Spear-phishing) is on the rise, and companies have already reported losses of 2.3 Billion dollars. Mattel made headlines for falling prey to CEO Fraud, when an employee sent a wire transfer of 2 million dollars to a bank in China. 

Other forms of spear-phishing attacks are on the rise, spreading ransomware variants like cryptowall. Surveys have shown that 30% of employees will open these types of emails. The ransoms paid in 2015 have amounted to a 500 billion dollar industry for cyber criminals.

A recent report from Trend Micro revealed that 81% of data breaches originated from phishing attacks. Therefore, email security should be a top priority for companies to protect themselves from these threats.

Here are my top 10 tips you can do to protect your company from these threats.

  1. Have employees participate in Security Awareness Training
  2. Phish your employees and train the ones who click on the false links
  3. Maintain regular backups offline. This may be your last line of defense if an employee or server becomes infected with ransomware.
    Note: Cloud based backups may be targeted, so traditional off-site rotation may need to be brought back for many companies who have switched to Disk to Disk only solutions.  Consider WORM drives to write to, (write once, read many) so that the original backup cannot be overwritten by cryptolocker type variants.
  4. Keep systems patched regularly. This reduces the surface attack area for advanced persistent threats (APT) to spread into your network.
  5. Block Executables at Mail Filter. This can prevent some forms of ransomware from coming into your environment.
  6. Implement DMARC to prevent spear-phishing attacks that pose from trusted executives. My how-to guide for implementing DMARC is here.
  7. Implement Zero Day email security protection solutions like MSFT ATP
  8. Implement application white-listing Solutions like Carbon Black (formerly known as Bit9) or Cylance
  9. Hide file shares, ex: \\server\share$. This prevents ransomware from scanning and finding file servers on the network.
  10. Replace Mapped Network Drives with shortcuts on Desktop to shared drives. This too can prevent ransomware from spreading. Implement principle of least privilege so that ransomware is limited to what it can write to.

Honorable mentions:
Cryptolocker Prevention Kit “The kit includes an article on cleaning up after infection but more importantly provides materials and instruction for deploying preventative block using software restriction policies. The articles provide instruction for installing them via GPO on domain computers and terminal servers, and non-domain joined machines too. We have also provide GPO settings that you can important into your environment.”
Individual Windows users should check out CryptoPrevent, a tiny utility from John Nicholas Shaw

You may have noticed that removing users from local administrator is not listed in the top 10. This is because CryptoLocker variants can execute without local admin privs.

How to stop email spoofing using DMARC

Did you know that 91% of successful data breaches started with a spear-phishing attack? (According to research from Trend Micro).

Two of my customers have informed me that their top executives’ email have been ‘spoofed’ by hackers. I have included the message headers from those spoofed emails in the blog post below (scrubbing the names to protect the innocent).

The hackers are exploiting a weakness in the Simple Mail Transport Protocol (SMTP) to masquerade themselves as a top executive, who then send an urgent email to staff to click a hyperlink or open an attachment. You can imagine what happens next: the computers get infected by Ransomware like CryptoLocker, encrypting not only hard drives, but also entire departmental file shares. Check your backups – this may be your only option to recover data that has been encrypted. The latest variants of ransomware are now trying to erase network connected backup storage too – so be extra vigilant to keep an offline copy of your backups.  

So when my customers asked me what they can do to prevent email spoofing,  I asked for a copy of the message headers that the attackers used and found out that the emails were getting through despite failing Sender Policy Framework (SPF) checks. SPF checks are the most common method to combat email spoofing. In this article I will describe how DMARC can better enforce your SPF record values to prevent spoofed email from passing through. I recently did a survey of 200 companies and found that only 12% have implemented DMARC so far. 

SPF is implemented by creating a type of DNS record called a ‘TXT’ that contains an authorized list of senders for that particular email domain. However, many companies have not implemented the most hardened syntax for the SPF record, known as the hard fail “-all.” Instead, they are implementing the soft fail “~all.” This allows for emails that do not match the authorized list of servers to pass through, albeit with a higher spam confidence level (SCL) score. 

Up until recently, it seemed as if SPF was all that was required to cause email filters to adjust the SCL high enough to cause spoofed emails to go into a quarantine or junk mail folder. All that started to change when the attackers started to use valid email servers hosted by trusted email providers such as GoDaddy. This caused the SCL score to be low enough for the email to pass through as legitimate “enough” to look like a standard email.

Additionally, and probably more significantly, hackers are now spoofing the RFC 5322.From header which cannot be detected by an SPF check. SPF is great for protecting against attacks where the 5321.MailFrom header is spoofed. Where SPF has problems is when the 5322.From header (the address that you see in Outlook).

Scroll down to see the (scrubbed) message headers in detail.

How do we stop spoofed emails?

Enter DMARC, which stands for “Domain-based Message Authentication, Reporting & Conformance”, is an email authentication protocol. It builds on the widely deployed SPF and DKIM protocols, and was submitted as RFC 7489 on March 18th 2015.

In a nutshell, DMARC is another type of DNS TXT record that builds on SPF and DKIM records and can be configured to specifically tells email filters to reject emails that did not originate from the senders authorized from the SPF or DKIM records. This is enough to stop spoofed emails cold in their tracks. Here is an example of a DMARC record:

v=DMARC1; p=quarantine; rua=mailto:postmaster@myemaildomain.com 

What this does is to send items to quarantine if the SPF record or DKIM checks fail, and to send reports to an email address that you specify. 

Prior to implementing a DNS record type for DMARC, it is important to talk to your marketing department for a list of companies that they send emails through, for example MailChimp. Those services must be in the SPF record otherwise they will be rejected. After the SPF has been updated, the hardfail setting should be changed to “-all” and the DMARC setting should be configured to reject. Organizations that aren’t sure which services their marketing companies are using can enable DMARC in monitoring mode so that they can first learn who is sending emails out. 

To test out your email system, you can send emails to these addresses and get a report back:

1. If you wish to receive the results at the address in the “mail_from,” the sample message should be sent to check-auth@verifier.port25.com.

2. If you wish to receive the results at the address in the “from” header, the sample message should be sent to check-auth2@verifier.port25.com.


Disclaimer: All content provided is for informational purposes only. Use at your own risk. 

Message Header Analysis

Take a look at these two spoofed message header (names have been changed to protect the innocent): 

First Example – Spoofed email originating from GoDaddy

Authentication-Results: spf=permerror (sender IP is
smtp.mailfrom=contoso.com; contoso.com; dkim=none (message not signed)
header.d=none;contoso.com; dmarc=none action=none header.from=contoso.com;
Received-SPF: PermError (protection.outlook.com: domain of contoso.com used an
invalid SPF mechanism)
(envelope-from <RealCEO@contoso.com>)
From: (Real CEO’s Full Name) RealCEO@contoso.com <– RFC 5322.From
To: (Unsuspecting End-User – Probably in Accounting Department) <AccountingClerk@contoso.com>
Subject: Let Me Know Asap!!
Reply-To: <ppdtml@mail.com> (Attacker’s address, or unsuspecting innocent 3rd party)
Mail-Reply-To: ppdtml@mail.com (Attacker’s address, or unsuspecting innocent 3rd party)
X-Sender: RealCEO@contoso.com
X-AntiAbuse: Primary Hostname – p3plcpnl0222.prod.phx3.secureserver.net
X-AntiAbuse: Original Domain – contoso.com
X-AntiAbuse: Sender Address Domain – contoso.com
X-Get-Message-Sender-Via: p3plcpnl0222.prod.phx3.secureserver.net: authenticated_id: noreply@(LegitimateEmailDomainAtGoDaddy)
Return-Path: RealCEO@contoso.com

Second Example – Spoofed email originating from POBOX.com

Return-Path: <RealCEO@contoso.com>
X-Env-Sender: RealCEO@contoso.com
X-SpamWhitelisted: domain whitelist
X-StarScan-Version: 8.11; banners=contoso.com,-,contoso.com
X-VirusChecked: Checked
Received: (qmail 121067 invoked from network); 21 Mar 2016 16:38:30 -0000
Received: from pb-sasl-trial1.pobox.com (HELO pb-sasl-trial1.pobox.com)
DHE-RSA-AES256-GCM-SHA384 encrypted SMTP; 21 Mar 2016 16:38:30 -0000
Received: from pb-sasl-trial1.pobox.com (localhost []) by
pb-sasl-trial1.pobox.com (Postfix) with ESMTP id 8D0A21017B for
<AccountingClerk@contoso.com>; Mon, 21 Mar 2016 12:38:30 -0400 (EDT)
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=mime-version
Received: from pb-wm-sasl1.int.icgroup.com (pb-wm-sasl1.int.icgroup.com
[]) by pb-sasl-trial1.pobox.com (Postfix) with ESMTP id 7F0521017A
for <AccountingClerk@contoso.com>; Mon, 21 Mar 2016 12:38:30 -0400 (EDT)
Received: from webmail.pobox.com (unknown []) (using TLSv1.2 with
cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate
requested) by pb-wm-sasl1.pobox.com (Postfix) with ESMTPSA id 0A27539EC9 for
<AccountingClerk@contoso.com>; Mon, 21 Mar 2016 12:38:30 -0400 (EDT)
Date: Mon, 21 Mar 2016 17:38:29 +0100
From: Real CEO’s Full Name RealCEO@contoso.com <– RFC 5322.From
To: <AccountingClerk@contoso.com>
Subject: Invoice Payment
Reply-To: <reply_r@aol.com> (Attacker’s address, or unsuspecting innocent 3rd party)
Mail-Reply-To: reply_r@aol.com (Attacker’s address, or unsuspecting innocent 3rd party)
X-Sender: RealCEO@contoso.com
User-Agent: Roundcube Webmail/1.1.1
X-Pobox-Relay-ID: 57FC50A6-EF83-11E5-B2BA-E24DCCAB2AED-19029152!pb-wm-sasl1.int.icgroup.com.pobox.com
X-MS-Exchange-Organization-AuthSource: RealExchangeServerHostName.contoso.com
X-MS-Exchange-Organization-AuthAs: Anonymous

And here is how authentic the email would look to the recipient:

—–Original Message—–
From: Real CEO’s Full Name [mailto:RealCEO@contoso.com]
Sent: Monday, March 21, 2016 9:53 AM
To: (Unsuspecting End-User – Probably in Accounting Department) <AccountingClerk@contoso.com>
Subject: RE: Invoice Payment


I need you to process an urgent payment, which needs to go out today as a same value day payment. Let me know when you are set to proceed, so i can have the account information forwarded to you once received.

Awaiting your response.


Sent from my iPad

I am in the office today.

—–End Original Message—–

O365 and DMARC

Because SPF fails, and because DKIM can fail, and because this is all due to routing, EOP will not enforce DMARC failures if your primary MX does not point to EOP. EOP can still detect if a message passes DMARC when the DKIM-signature passes.


For Office 365 customers, if you do not set the DMARC value to p=reject, then it is recommended to create a message transport rule to set the spam confidence level to 9 so that it doesn’t hit the user’s inbox. The advantage of this is that your domain cannot be spoofed by outside senders for inbound messages to your organization which is common in spear phishing, yet marketing messages that go over the Internet are not affected.



In the first example, the email passed through the Exchange Online Protection filters. In the second example, the email was passed through MessageLabs filters. In the second example, since there was no hyperlink or attachment, we can only assume that the reply TO address was the attacker’s actual email address. Whereas in the first example, the reply TO address was forged because the attacker only wanted the recipient to click on a hyperlink.

After implementing DMARC, the message header section “Authentication-Results”  will contain instructions to reject both of these emails.

Dmarc relies upon SPF *or* DKIM. So if you can’t do outbound DKIM signing, you can still enforce DMARC on an SPF hard fail to prevent inbound mail from coming through as spoofed.

Advanced Threat Protection from compromised Vendors

DMARC provides an excellent layer of defense to add to your defense in depth security policy, preventing spoofed mails from reaching your internal users. For situations where an attacker is not spoofing your domain, but is instead spoofing one of your trusted Vendors domains, DMARC would have to be implemented by your Vendor before it would protect you. In the trusted Vendor scenario, you can best protect yourself by adding an advanced layer of protection to scan for phishing hyperlinks and zero-day vulnerabilities that are not yet in virus definition files. One such solution is Microsoft Advanced Threat Protection (ATP). ATP will detonate attachments in a cloud-hosted virtual machine and observe it for malicious intent before delivering it to your end-users. It will also replace Hyperlinks with ‘safe links’ which are scanned at the time the user clicks on the hyperlink. For more information on Advanced Threat Protection, or to schedule a free consultation to have Patriot Consulting configure it in your Office 365 tenant free-of-charge, contact us at hello@patriotconsultingtech.com.


Demarc Deployment Tools, Generators and Checks: ttps://dmarc.org/resources/deployment-tools/

For more information on DMARC, check out www.dmarc.org