Author Archives: Michel de Rooij

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About Michel de Rooij

Michel de Rooij, with over 25 years of mixed consulting and automation experience with Exchange and related technologies, is a consultant for Rapid Circle. He assists organizations in their journey to and using Microsoft 365, primarily focusing on Exchange and associated technologies and automating processes using PowerShell or Graph. Michel's authorship of several Exchange books and role in the Office 365 for IT Pros author team are a testament to his knowledge. Besides writing for Practical365.com, he maintains a blog on eightwone.com with supporting scripts on GitHub. Michel has been a Microsoft MVP since 2013.

Outlook Connectivity changes per Nov2021

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In the past, using outdated clients with Microsoft 365 services was a matter of being in an unsupported state with all the risks that go with it. This meant, that things might not work or you could experience reduced functionality. Overall, things usually kept working with a few consequences or glitches here and there.

A change in this stance was announced today per Message Center bulletin MC229143:

To ensure that we meet performance expectations, we are updating the supported versions of Outlook for Windows that can connect to Microsoft 365 services. Effective November 1, 2021, the following versions of Outlook for Windows, as part of Office and Microsoft 365 Apps, will not be able to connect with Office 365 and Microsoft 365 services.

This means, running old unsupported Outlook versions will go from “possible performance and reliability issues” to becoming actively blocked. This block will apply to these versions in the table below; as indicated, these builds were surpassed somewhere in 2017:

ApplicationAffected BuildsBuild Superseded
Office 201315.0.4970.9999
and older		October 2017
Office 201616.0.4599.9999
and older		October 2015
Microsoft 365 Apps for Enterprise
(formerly Office 365 ProPlus)

Microsoft 365 Apps for Business
(formerly Office 365 Business

1705 and olderJune 2017

While it is true that many customers are stretching the lifetime of their on-premises products beyond their support dates, I’m sure – apart from functionality and management options – performance and reliability is becoming more and more of an issue.

Finally, when this notice concerns you, it means you have not been updating your clients for at least 3 years. So, get planning, as you have around 11 months to update your clients. It also may affect any existing plans of moving to Exchange Online in the future, as getting your client-base in a supported state will become a requirement, and will no longer be a serious recommendation.

Security Updates Exchange 2010-2019 (Dec2020)

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A quick blog on security updates for Exchange Server 2013, 2016 and 2019 released December 8th. These fixes address the following vulnerability:

Exchange 2016 / 2019

  • CVE-2020-17117: Microsoft Exchange Remote Code Execution Vulnerability
  • CVE-2020-17132: Microsoft Exchange Remote Code Execution Vulnerability
  • CVE-2020-17141: Microsoft Exchange Remote Code Execution Vulnerability
  • CVE-2020-17142: Microsoft Exchange Remote Code Execution Vulnerability
  • CVE-2020-17143: Microsoft Exchange Information Disclosure Vulnerability

Exchange 2013

  • CVE-2020-17117: Microsoft Exchange Remote Code Execution Vulnerability
  • CVE-2020-17132: Microsoft Exchange Remote Code Execution Vulnerability
  • CVE-2020-17142: Microsoft Exchange Remote Code Execution Vulnerability
  • CVE-2020-17143: Microsoft Exchange Information Disclosure Vulnerability

Exchange 2010

  • CVE-2020-17144: Microsoft Exchange Remote Code Execution Vulnerability

The exploits can be fixed by single security update, which you can find in the table below per current Exchange version.

ExchangeDownloadBuildKBSupersedes
Exchange 2019 CU7Download15.2.721.6KB4593465KB4588741
Exchange 2019 CU6Download15.2.659.11KB4593465KB4588741
Exchange 2016 CU18Download15.1.2106.6KB4593465KB4588741
Exchange 2016 CU17Download15.1.2044.12KB4593465KB4588741
Exchange 2013 CU23Download15.0.1497.10KB4593466
Exchange 2010 SP3 RU31 Download14.3.509.0KB4593467

Be advised that these security updates are Cumulative Update level specific. You cannot apply the update for Exchange 2016 CU17 to Exchange 2016 CU16. Also, the security update download has the same name for different Cumulative Updates, and I would suggest tagging the file name with the CU level, e.g. Exchange2019-CU6-KB4588741-x64-en.msp.

Also, run the Security Update from an elevated command prompt, to prevent issues during installation. And on a final note, as with any patch or update, I’d recommend to apply this in a acceptance environment first, prior to implementing it in production.

Security Updates Exchange 2013-2019 (Nov2020)

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A quick blog on security updates for Exchange Server 2013, 2016 and 2019 released November 10th. These fixes address the following vulnerability:

  • CVE-2020-17085: Microsoft Exchange Server Denial of Service Vulnerability
  • CVE-2020-17084: Microsoft Exchange Server Remote Code Execution Vulnerability
  • CVE-2020-17083: Microsoft Exchange Server Remote Code Execution Vulnerability

The exploits can be fixed by single security update, which you can find in the table below per current Exchange version.

ExchangeDownloadBuildKBSupersedes
Exchange 2019 CU7Download15.2.721.4KB4588741KB4581424
Exchange 2019 CU6Download15.2.659.8KB4588741KB4581424
Exchange 2016 CU18Download15.1.2106.4KB4588741KB4581424
Exchange 2016 CU17Download15.1.2044.8KB4588741KB4581424
Exchange 2013 CU23Download15.0.1497.8KB4588741KB4581424

Be advised that these security updates are Cumulative Update level specific. You cannot apply the update for Exchange 2016 CU17 to Exchange 2016 CU16. Also, the security update download has the same name for different Cumulative Updates, and I would suggest tagging the file name with the CU level, e.g. Exchange2019-CU6-KB4588741-x64-en.msp.

Also, run the Security Update from an elevated command prompt, to prevent issues during installation. And on a final note, as with any patch or update, I’d recommend to apply this in a acceptance environment first, prior to implementing it in production.

Security Updates Exchange 2013-2019 (Oct2020)

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A quick blog on security updates for Exchange Server 2013, 2016 and 2019 released October 13th. These fixes address the following vulnerability:

  • CVE-2020-16969: Microsoft Exchange Information Disclosure Vulnerability
    An information disclosure vulnerability exists in how Microsoft Exchange validates tokens when handling certain messages. An attacker who successfully exploited the vulnerability could use this to gain further information from a user.

    To exploit the vulnerability, an attacker could include specially crafted OWA messages that could be loaded, without warning or filtering, from the attacker-controlled URL. This callback vector provides an information disclosure tactic used in web beacons and other types of tracking systems.

    The security update corrects the way that Exchange handles these token validations.

The exploits can be fixed by single security update, which you can find in the table below per current Exchange version.

ExchangeDownloadBuildKBSupersedes
Exchange 2019 CU7Download15.2.721.3KB4581424KB4577352
Exchange 2019 CU6Download15.2.659.7KB4581424KB4577352
Exchange 2016 CU18Download15.1.2106.3KB4581424KB4577352
Exchange 2016 CU17Download15.1.2044.7KB4581424KB4577352
Exchange 2013 CU23Download15.0.1497.7KB4581424KB4536988

Be advised that these security updates are Cumulative Update level specific. You cannot apply the update for Exchange 2016 CU17 to Exchange 2016 CU16. Also, the security update download has the same name for different Cumulative Updates, and I would suggest tagging the file name with the CU level, e.g. Exchange2016-CU17-KB4581424-x64-en.msp.

Also, run the Security Update from an elevated command prompt, to prevent issues during installation. And on a final note, as with any patch or update, I’d recommend to apply this in a acceptance environment first, prior to implementing it in production.

EWS.WebServices.Managed.Api

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A short blog on the EWS Managed API and using the latest version with scripts leveraging Exchange Web Services (EWS), such as my Remove-DuplicateItems script. The installable EWS Managed API library was last updated in 2014 (version 2.2, reports as v15.0.913.22), and there have been few enhancements since then. These are included in the EWS.WebServices.Managed.Api package, which carries version 2.2.1.2.

Although this library was last updated in 2019, you might still need it to successfully run EWS scripts. The EWS.WebServices.Managed.Api package supports some Exchange Web Services calls which are not supported in the 2.2 version, and may lead to error messages like Exception calling “FindFolders” with “2” argument(s) or other messages related to the (number of) arguments. This may be an indication a particular call was used to one of the EWS functions, but which is not supported by the installed EWS Managed API library. In those cases, installing this updated library might help.

The library is published on NUGet as a package. To install the package, we first need to register NuGet as a Package Source:

Register-PackageSource -provider NuGet -name nugetRepository -location https://www.nuget.org/api/v2

Next, install the package from the newly defined NuGet source:

Install-Package Exchange.WebServices.Managed.Api

The package installs by default under C:\Program Files\PackageManagement\NuGet\Packages. I have updated my scripts to include this location when searching for the required Microsoft.Exchange.WebServices.dll as well. Alternatively, you can copy this DLL from the ..\Exchange.WebServices.Managed.Api.<Version>\lib\net35 folder to the location where the script resides. When running my EWS-based scripts in Verbose mode, it will report as version 2.2.1.0.

Hopefully this blog will potentially save you some time troubleshooting, and myself answering some support messages. Enjoy!