Security Updates Exchange 2013-2019

Exchange2019LogoA quick blog on recently published security updates for Exchange Server 2013 up to Exchange Server 2019. These fixes address the following vulnerabilities:

  • CVE-2019-1373: Microsoft Exchange Remote Code Execution Vulnerability

The CVE documents contain more details on the vulnerabilities. The exploits can be fixed by single security update, which you can find in the table below per current Exchange version.

ExchangeDownloadBuildKBSupersedes
Exchange 2019 CU3Download15.2.464.7 KB4523171KB4515832
Exchange 2019 CU2Download15.2.397.9 KB4523171 KB4515832
Exchange 2016 CU14Download15.1.1847.5 KB4523171 KB4515832
Exchange 2016 CU13Download15.1.1779.7 KB4523171 KB4515832
Exchange 2013 CU23Download15.0.1497.4 KB4523171 KB4509409

Be advised that the Security Updates for Exchange 2013-2019 are Cumulative Update level specific. Unfortunately, the security update carries the same name for different CUs, and you cannot apply the update for Exchange 2016 CU14 to Exchange 2016 CU13. I would suggest tagging the Cumulative Update in the file name when you store it, e.g. Exchange2016-CU14-KB4523171-x64-en.msp.

As with any patch or update, I’d recommend to apply this in a acceptance environment first, prior to implementing it in production.

Exchange Hybrid Agent GA

Ex2013 LogoIn February, Microsoft released the initial public preview version of the Hybrid Agent. The purpose of the Hybrid Agent, also branded as the “Exchange Modern Hybrid Topology”, is to simplify the process of setting up and deploying Microsoft Exchange Hybrid for Exchange 2010 and later deployments, where full “classic” Exchange Hybrid is not an option.

It can also address scenarios where deploying the Hybrid Agent would satisfy organizational migration requirements. For example, moving mailboxes between Exchange Online and Exchange on-premises while providing rich-coexistence features, but without requiring (re)configuration of the publishing of Exchange services. Other functionality the Hybrid Agent doesn’t offer is mail transport. Future builds of the Hybrid Agent might introduce cross-premises functionality, such as Send As delegations as demonstrated at Microsoft Ignite last year.

This week, the Hybrid Agent Public reached General Availability status. In the following article for ENow, I discuss the major changes in the agent since the initial Preview release.

Read the full article on the ENow Software blog.

ADV190018: Security Updates Exchange 2013-2019 & 2010

Ex2013 LogoUpdated Jun13: Corrected Ex2010SP3RU28 link

A quick note that an update was released for current Exchange versions as well as Exchange 2010 related to the following advisory:

  • ADV190018 Microsoft Exchange Server Defense in Depth Update

Unfortunately – or perhaps understandably – the advisory doesn’t present any more details than, ‘”Microsoft has released an update for Microsoft Exchange Server that provides enhanced security as a defense in depth measure.”.

You can download the security updates here:

Be advised that the Security Updates for Exchange 2013-2019 are Cumulative Update level specific. Unfortunately, the security update carries the same name for different CU’s, and you cannot apply the update for Exchange 2016 CU12 to Exchange 2016 CU11. I would suggest tagging the Cumulative Update in the file name when you store it, e.g. Exchange2016-KB4503027-x64-en_CU11.msp.

As with any patch or update, I’d recommend to apply this in a acceptance environment first, prior to implementing it in production.

Exchange Updates – February 2019

Update: Added note that Exchange 2010 SP3 RU26 adds support for Windows Server 2012 R2.

Today, the Exchange Team released the overdue quarterly Cumulative Updates for Exchange Server 2013, Exchange 2016 and Exchange 2019, as well as a Rollup for Exchange Server 2010.

The KB articles that describe the fixes in each release and product downloads are available as follows:

Version Build KB Download UMLP Schema
Exchange 2019 CU1 15.2.330.5 KB4471391 VLSC N
Exchange 2016 CU12 15.1.1713.5 KB4471392 Download UMLP N
Exchange 2013 CU22 15.0.1473.3 KB4345836 Download UMLP N
Exchange 2010 SP3 RU26 14.3.442.0 KB4487052 Download N

This update contain the following important changes and notes:

  • Due to issue CVE-2018-8581, the EWS architecture was changed, in particular push notifications. Details on the change are described in KB4490060; while the change has been tested against EWS clients such as Outlook for Mac and Skype for Business, organizations may need to test any applications leveraging EWS to estimate potential impact of installing these Cumulative Updates or Rollup. In addition, organizations are advised to password reset Exchange computer accounts.
  • These Exchange builds introduces a change in the shared permissions model (this does not apply to Split Permissions Model). Result is that Exchange no longer requires fargoing permissions in Active Directory (e.g. WriteDACL on root of domain). To makes these changes become effective:
    • For Exchange 2013-2019 Cumulative Updates, run setup using /PrepareAD. In multi-forest environments, this needs to be done in every domain of the forest.
    • For Exchange 2010, go through the instructions mentioned in KB4490059.
  • Organizations considering moving to the Split Permissions because of CVE-2018-8581 should know Microsoft fully supports both models. Switching can have serious consequences and therefor should be fully evaluated.
  • This build of Exchange 2019 introduces cmdlets to block usage of legacy authentication protocols for users through policies, e.g. Basic Authentication.
  • Prior to deploying Exchange 2016 CU12 or Exchange 2013 CU22 on Edge Transport servers, install Visual C++ 2012 Runtime.
  • These Cumulative Updates will remove the DisableLoopbackCheck key when present; removing this key was a mitigation for CVE-2018-8581.
  • Exchange 2010 SP3 RU26 adds support for Windows Server 2012 R2, to accommodate for the Hybrid Agent.

Exchange 2019 CU1 fixes:

  • 4487596 Emails are blocked in moderator mailbox Outbox folder when you send large volumes of emails in Exchange Server 2019
  • 4487591 The recipient scope setting doesn’t work for sibling domains when including OUs in the scope in Exchange Server 2019
  • 4487602 Outlook for Mac users can still expand a distribution group when hideDLMembership is set to true in Exchange Server 2019
  • 4488076 Outlook on the Web can’t be loaded when users use an invalid Windows language in operating system in Exchange Server 2019
  • 4488079 Exchange Server 2016 allows adding Exchange Server 2019 mailbox server into a same DAG and vice versa
  • 4488263 X-MS-Exchange-Organization-BCC header isn’t encoded correctly in Exchange Server 2019
  • 4488080 New-MigrationBatch doesn’t honor RBAC management scope in Exchange Server 2019
  • 4488262 Delivery Reports exception when tracking a meeting request that’s sent with a room resource in Exchange Server 2019
  • 4488268 Disable the irrelevant Query logs that’re created in Exchange Server 2019
  • 4488267 Test-OAuthConnectivity always fails when Exchange Server uses proxy to connect to Internet in Exchange Server 2019
  • 4488266 Client application doesn’t honor EwsAllowList in Exchange Server 2019
  • 4488265 “There are problems with the signature” error occurs for digital signature message if attachment filtering is enabled in Exchange Server 2019
  • 4488398 “The Microsoft Exchange Replication service may not be running on server” error when you add a mailbox database copy in Exchange Server 2019
  • 4488264 Mailbox that has a bad move request can’t be cleaned up from destination mailbox database in Exchange Server 2019
  • 4488261 Event ID 1002 when the store worker process crashes in Exchange Server 2019
  • 4488260 New-MailboxExportRequest and New-MailboxImportRequest don’t honor RBAC management scope in Exchange Server 2019
  • 4488259 MailTip shows wrong number of users for a distribution group if the users are in different domains in Exchange Server 2019
  • 4488258 OAuth authentication is removed when saving MAPI virtual directory settings in EAC in Exchange Server 2019
  • 4490060 Exchange Web Services Push Notifications can be used to gain unauthorized access
  • 4490059 Reducing permissions required to run Exchange Server using Shared Permissions Model

Exchange 2016 CU12 fixes:

  • 4487596 Emails are blocked in moderator mailbox Outbox folder when you send large volumes of emails in Exchange Server 2016
  • 4456241 You receive a meeting request that has a “not supported calendar message.ics” attachment in Exchange Server 2016
  • 4456239 New-MailboxRepairRequest doesn’t honor RBAC RecipientWriteScope restrictions in Exchange Server 2016
  • 4487591 The recipient scope setting doesn’t work for sibling domains when including OUs in the scope in Exchange Server 2016
  • 4468363 MRM does not work for mailboxes that have an online archive mailbox in Exchange Server
  • 4487603 “The action cannot be completed” error when you select many recipients in the Address Book of Outlook in Exchange Server 2016
  • 4487602 Outlook for Mac users can still expand a distribution group when hideDLMembership is set to true in Exchange Server 2016
  • 4488076 Outlook on the Web can’t be loaded when users use an invalid Windows language in operating system in Exchange Server 2016
  • 4488079 Exchange Server 2016 allows adding Exchange Server 2019 mailbox server into a same DAG and vice versa
  • 4488077 Can’t configure voice mail options when user is in different domain in Exchange Server 2016
  • 4488263 X-MS-Exchange-Organization-BCC header isn’t encoded correctly in Exchange Server 2016
  • 4488080 New-MigrationBatch doesn’t honor RBAC management scope in Exchange Server 2016
  • 4488262 Delivery Reports exception when tracking a meeting request that’s sent with a room resource in Exchange Server 2016
  • 4488268 Disable the irrelevant Query logs that’re created in Exchange Server 2016
  • 4488267 Test-OAuthConnectivity always fails when Exchange Server uses proxy to connect to Internet in Exchange Server 2016
  • 4488266 Client application doesn’t honor EwsAllowList in Exchange Server 2016
  • 4488265 “There are problems with the signature” error occurs for digital signature message if attachment filtering is enabled in Exchange Server 2016
  • 4488264 Mailbox that has a bad move request can’t be cleaned up from destination mailbox database in Exchange Server 2016
  • 4488261 Event ID 1002 when the store worker process crashes in Exchange Server 2016
  • 4488260 New-MailboxExportRequest and New-MailboxImportRequest don’t honor RBAC management scope in Exchange Server 2016
  • 4488259 MailTip shows wrong number of users for a distribution group if the users are in different domains in Exchange Server 2016
  • 4488258 OAuth authentication is removed when saving MAPI virtual directory settings in EAC in Exchange Server 2016
  • 4490060 Exchange Web Services Push Notifications can be used to gain unauthorized access
  • 4490059 Reducing permissions required to run Exchange Server using Shared Permissions Model

Exchange 2013 CU22 fixes:

  • 4487603 “The action cannot be completed” error when you select many recipients in the Address Book of Outlook in Exchange Server 2013
  • 4490060 Exchange Web Services Push Notifications can be used to gain unauthorized access
  • 4490059 Reducing permissions required to run Exchange Server using Shared Permissions Model

Exchange 2010 SP3 RU26 fixes:

  • 4490060 Exchange Web Services Push Notifications can be used to gain unauthorized access

Notes:

  • These Cumulative Updates do not contain schema changes compared to their previous Cumulative Update. However, due to changes in the permissions architecture, you need to run setup /PrepareAD to implement these changes as well as apply any RBAC changes, before deploying or updating Exchange servers.
  • When upgrading from an n-2 or earlier version of Exchange, or an early version of the .NET Framework, consult Upgrade Paths for CU’s & .NET.
  • Don’t forget to put the Exchange server in maintenance mode prior to updating. Regardless, setup will put the server in server-wide offline mode post-analysis, before making actual changes.
  • When using Exchange hybrid deployments or Exchange Online Archiving (EOA), you are required to delay installing at most one version (n-1).
  • If you want to speed up the update process for systems without internet access, you can follow the procedure described here to disable publisher’s certificate revocation checking.
  • Cumulative Updates can be installed directly; no need to install RTM prior to installing Cumulative Updates.
  • Once installed, you can’t uninstall a Cumulative Update nor any of the installed Exchange server roles.
  • The order of installation shouldn’t matter with the “every server is an island” concept, yet recommended is to upgrade internet-facing, non-internet-facing servers first, followed by Edge Transports.

Caution:

As for any update, I recommend to thoroughly test updates in a test environment prior to implementing them in production. When you lack such facilities, hold out a few days and monitor the comments on the original publication or forums for any issues.

CVE-2018-8581: Exchange Vulnerability

Ex2013 LogoUpdate Feb6: Added MSRC security advisory ADV190007 .
Update Feb13: February updates comment.

A short notice on the zero-day vulnerability in the Exchange ecosystem as reported by researcher Mollema last week. Through a man-in-the-middle setup, one can exploit the permissions Exchange has with regards to Active Directory in conjunction with NTLM as well as Exchange Web Services (EWS). This 3-stage missile allows one to elevate their privileges in Active Directory, and thus to grant themselves administrative access.

The issue was already logged at 13 november in the Microsoft Security Response Center (MSRC) as CVE-2018-8581, Microsoft Exchange Server Elevation of Privilege Vulnerability. An uptake on the public attention for the issue was generated after the Mollema article, and media like The Register started publishing about it. Meanwhile Exchange fellow Tony Redmond also wrote a short note on the issue as well.

At this moment, Microsoft is fully aware of the issue, and is actively working on resolving the issue as soon as possible. Meanwhile, the mitigation mentioned in CVE-2018-8581 can be considered, which is to remove the  DisableLoopbackCheck key from HKLM:\SYSTEM\CurrentControlSet\Control\Lsa. The effect of removing this key is that it’s no longer possible to make NTLM connections on the loopback adapter (localhost), which should be OK for Kerberos authenticated sessions as they are name-based. Again, test this as for example platforms like SharePoint will break when setting this key, but nobody runs SharePoint on the same box, so for Exchange this is a valid mitigation.

Organizations are advised not to blindly implement mitigations mentioned in Mollema’s article or elsewhere in the field, as they might not be applicable to every deployment out there, or have unforseen side-effects. Then again, organizations might already have things deployed SMB signing, in which case the exploit does not apply.

Update (Feb6): Meanwhile, Microsoft Security Response Center published an advisory (ADV190007) containing guidance on how to deal with the issue at this moment. MSRC takes the EWS Throttling Policy route to block EWS Subscriptions at the original level, which of course breaks Outlook for Mac functionality (e.g. new mail notifications as the client can no longer subscribe to receive updates), or other applications which rely on this mechanism (e.g. meeting room systems). This can be mitigated by explicitly allowing EWS subscriptions for trusted users and applications.

Update (Feb13): Today the quarterly cumulative updates for Exchange 2019/2016/2013 were released, which will remove the DisableLoopbackCheck key (when present).

Security Updates Exchange 2013, 2016 & 2019

Ex2013 LogoUpdate 14jan: Added Exchange 2010 SP3 RU25

A quick heads-up as during my vacation Microsoft released security updates for supported releases of Exchange Server 2013, 2016 as well as Exchange Server 2019. In addition, a new Rollup was released for Exchange 2010 as well, containing one of the security updates.

The security updates patch issues as reported in the following Microsoft Common Vulnerabilities and Exposures:

  • CVE-2019-0586: Microsoft Exchange Memory Corruption Vulnerability
  • CVE-2019-0588: Microsoft Exchange Information Disclosure Vulnerability

You can download the security updates here:

Notes:

  • Exchange 2010 SP3 RU25 addresses CVE-2019-0588 only.
  • KB4471389 supersedes KB4468741 and KB4459266; KB4468742 supersedes KB4458321.

Be advised that the Security Updates for Exchange 2013 and 2016 are Cumulative Update level specific. Unfortunately, the security update carries the same name for different CU’s, and you cannot apply the update for Exchange 2016 CU10 to Exchange 2016 CU11. I would suggest tagging the Cumulative Update in the file name when you archive it, e.g. Exchange2016-KB4471389-x64-en-CU10.msp.

As with any patch or update, I’d recommend to thoroughly test this in a test and acceptance environment first, prior to implementing it in production.

Security Updates for Exchange 2016, 2013 and 2010

Ex2013 LogoA quick heads-up as during my vacation Microsoft released security updates for supported releases of Exchange Server 2016 and 2013 as well as Exchange Server 2010.

The security updates patch issues as reported in the following Microsoft Common Vulnerabilities and Exposures:

  • CVE-2018-8302 Microsoft Exchange Memory Corruption Vulnerability
  • CVE-2018-8374 Microsoft Exchange Server Tampering Vulnerability (Exchange 2016 only)

You can download the security updates here:

Notes:

  • Be advised that Exchange 2010 SP3 Rollup 23, like recent Cumulative Updates of Exchange 2016 and 2013, requires Visual C++ Redistributable Packages for Visual Studio 2013 (download).
  • KB4340731 supersedes the previous security update KB4092041 for Exchange 2016 and Exchange 2013.

Be advised that for Exchange 2013 and 2016, Security Updates are Cumulative Update level specific. While the downloaded security updates may carry the same name, the files are different and you cannot apply the downloaded security update file for Exchange 2016 CU8 to Exchange 2016 CU9. I suggest adding some form of identification of the Cumulative Update to the file name when you archive it, e.g. Exchange2016-KB4340731-x64-en-CU10.msp.

As with any patch or update, I’d recommend to thoroughly test this in a test and acceptance environment first, prior to implementing it in production.

Exchange Updates – June 2018

Ex2013 LogoThe Exchange Team released the June updates for Exchange Server 2013 and 2016, and an additional Rollup 22 for Exchange Server 2010 Service Pack 3.

Apart from fixes and time zone changes, these updates contain the following important changes and notes:

  • As announced earlier, Exchange 2013 CU21 and Exchange 2016 CU10 require .NET Framework 4.7.1.
  • All three updates require the VC++ 2013 runtime library, because it is needed by a 3rd component in WebReady Document Viewing in Exchange 2010/2013 and Data Loss Prevention in Exchange 2013/2016. Exchange 2010 SP3 RU22 will force installation of this VC++ runtime.
  • Updates include a critical security patch for Oracle Outside In libraries. More about the issue in MSRC advisory ADV180010.
  • Exchange 2013 CU21 and Exchange 2016 CU10 introduce support for directly creating and enabling remote shared mailboxes, e.g.
    New-RemoteMailbox [-Shared] [-Name remoteMailboxName]
    Enable-RemoteMailbox [-Identity user] [-Shared] [-RemoteRoutingAddress user@domain]
    Set-RemoteMailbox [-Name user] [-Type Shared]

    You need to run setup /PrepareAD to see these changes. More information in KB4133605.

  • This is the last planned Cumulative Update for Exchange 2013 as it enters Extended Support.
  • Exchange 2010 SP3 RU22 adds support for Windows Server 2016 Domain Controllers.

 

Version Build KB Article Download UMLP Schema Changes
Exchange 2016 CU10 15.1.1531.3 KB4099852 Download UMLP No
Exchange 2013 CU21 15.0.1395.4 KB4099855 Download UMLP No
Exchange 2010 SP3 RU22 14.3.411.0 KB4295699 Download

Exchange 2016 CU10 fixes:

  • 4056609 Event ID 4999 and mailbox transport delivery service won’t start with Exchange Server 2016 CU7 installed
  • 4133605 Cmdlets to create or modify a remote shared mailbox in an on-premises Exchange environment
  • 4133620 “HTTP 500 due to ADReferralException” error when a user tries to view detail properties of mailboxes in a child domain in Exchange Server
  • 4095974 “System.InvalidOperationException” occurs when the “Enable-MailPublicFolder” cmdlet is run against a public folder in Exchange Server
  • 4095973 Set-ServerComponentState cmdlet does not honor the write scope defined in the RBAC management scope in Exchange Server
  • 4095993 HTTP 500 error when an administrator tries to manage regional settings in ECP on Windows Server 2016
  • 4294209 Cannot clear the “Maximum message size” check box for Send messages or Receive messages in EAC in Exchange Server 2016
  • 4294208 “TooManyObjectsOpenedException” error when you run the “Get-PublicFolderMailboxDiagnostics” cmdlet in Exchange Server
  • 4294212 Cannot send VBScript-created messages in the Outlook 2016 client
  • 4294211 Cannot run “Set-CalendarProcessing” cmdlets after you apply CU8 or CU9 for Exchange Server 2016
  • 4294210 Cannot edit an email attachment in OWA in an Exchange Server 2016 environment
  • 4294204 Changing “IsOutOfService” to “False” in an earlier Exchange Server version does not immediately update in a later Exchange Server environment
  • 4092041 Description of the security update for Microsoft Exchange Server 2013 and 2016: May 8, 2018

Exchange 2013 CU20 fixes:

  • 4133605 Cmdlets to create or modify a remote shared mailbox in an on-premises Exchange environment
  • 4133604 User can’t log on to a POP/IMAP account by using NTLM authentication in Exchange Server 2013
  • 4133618 Unexpected error occurs when running the Get-DatabaseAvailabilityGroupNetwork cmdlet in Exchange Server 2013
  • 4133620 “HTTP 500 due to ADReferralException” when a user tries to view detail properties of mailboxes in a child domain in Exchange Server
  • 4058473 An Office 365 primary mailbox user cannot be assigned full access permissions for an on-premises mailbox in Exchange Server
  • 4094167 The MSExchangeRPC service crashes with a System.NullReferenceException exception in Exchange Server 2013
  • 4095974 “System.InvalidOperationException” occurs when the “Enable-MailPublicFolder” cmdlet is run against a public folder in Exchange Server
  • 4092041 Description of the security update for Microsoft Exchange Server 2013 and 2016: May 8, 2018
  • 4294205 POP3 services intermittently stop in an Exchange Server 2013 environment
  • 4294204 Changing “IsOutOfService” to “False” in an earlier Exchange Server version does not immediately update in a later Exchange Server environment

Exchange 2010 Rollup 22 fixes:

  • 4295751 EWS impersonation not working when accessing resource mailboxes in a different site in Exchange Server 2010 SP3

Notes:

  • Exchange 2016 CU8 and Exchange 2013 CU18 do not contain schema changes compared to their previous Cumulative Update. However, they introduce RBAC changes in your environment. Use setup /PrepareAD to apply RBAC changes, before deploying or updating Exchange servers.
  • When upgrading from an n-2 or earlier version of Exchange, or an early version of the .NET Framework, consult Upgrade Paths for CU’s & .NET.
  • When upgrading your Exchange 2013 or 2016 installation, don’t forget to put the server in maintenance mode when required. Regardless, setup will put the server in server-wide offline mode post-analysis, before making actual changes.
  • When using Exchange hybrid deployments or Exchange Online Archiving (EOA), you are required to stay at most one version behind (n-1).
  • If you want to speed up the update process for systems without internet access, you can follow the procedure described here to disable publisher’s certificate revocation checking.
  • Cumulative Updates can be installed directly, i.e. no need to install RTM prior to installing Cumulative Updates.
  • Once installed, you can’t uninstall a Cumulative Update nor any of the installed Exchange server roles.
  • The order in which you upgrade servers with Cumulative Updates is irrelevant.

Caution:

As for any update, I recommend to thoroughly test updates in a test environment prior to implementing them in production. When you lack such facilities, hold out a few days and monitor the comments on the original publication or forums for any issues.

Security Updates for Exchange 2016, 2013 and 2010

Ex2013 LogoA quick heads-up for those that missed it that earlier this month, as Microsoft released security updates for supported releases of Exchange Server 2016 and 2013 as well as Exchange Server 2010.

The security updates patch issues as reported in the following Microsoft Common Vulnerabilities and Exposures:

  • CVE-2018-8151 – Microsoft Exchange Memory Corruption Vulnerability
  • CVE-2018-8154 – Microsoft Exchange Memory Corruption Vulnerability
  • CVE-2018-8159 – Microsoft Exchange Elevation of Privilege Vulnerability
  • CVE-2018-8153 – Microsoft Exchange Spoofing Vulnerability
  • CVE-2018-8152 – Microsoft Exchange Server Elevation of Privilege Vulnerability

You can download the security updates here:

You may notice that Exchange 2013 Service Pack 1 is still in there, but this is because Cumulative Updates and Service Packs are on a different servicing model. Every Cumulative Update is supported for three months after the release of the next Cumulative Update; Exchange 2013 SP1 entered extended support early April, and will only receive critical updates such as this one.

Be advised that for Exchange 2013 and 2016, Security Updates are Cumulative Update level specific. While the downloaded security updates may carry the same name, the files are different and you cannot apply the downloaded security update file for Exchange 2016 CU8 to Exchange 2016 CU9. I suggest adding some form of identification of the Cumulative Update to the file name when you save it, e.g. Exchange2016-KB4092041-x64-en-CU9.msp.

As with any patch or update, I’d recommend to thoroughly test this in a test and acceptance environment first, prior to implementing it in production.

 

Exchange Updates – March 2018

Ex2013 LogoThe Exchange Team released the March updates for Exchange Server 2013 and 2016, and these Cumulative Updates contain a ton of fixes. Like the earlier Cumulative Updates for Exchange 2013 and Exchange 2016, and in addition to the fixes – see below – these Cumulative Updates contain the following important changes:

  • Support for .NET Framework 4.7.1. Be advised that .NET Framework 4.7.1 will be required for the next cycle of quarterly updates, which will be released in June 2018.
  • Full support for TLS 1.2. More information and guidance here.

On a smaller note, Exchange 2010 Service Pack 3 Rollup 20 was also released, which contains two security fixes CVE-2018-0924 and CVE-2018-0940, as well as DST changes.

Version Build KB Article Download UMLP Schema Changes
Exchange 2016 CU9 15.1.1466.3 KB4055222 Download UMLP No
Exchange 2013 CU20 15.0.1367.3 KB4055221 Download UMLP No
Exchange 2010 SP3 RU20 14.3.389.1 KB4073537 Download

Exchange 2016 CU9 fixes:

  • 4054513 Mailbox usage status bar in OWA displays incorrect mailbox usage
  • 4055433 User is added to an entire series when accepting a single instance through Exchange ActiveSync
  • 4057216 Health mailbox’s password is exposed in logs for a failed probe in Exchange Server 2016 and 2013
  • 4058373 “A parameter cannot be found” error when you run Install-AntiSpamAgents.ps1 in Exchange Server 2016 CU7
  • 4058379 All cross-forest meeting updates have to be accepted again in Exchange Server 2016 and 2013
  • 4058383 Exchange Control Panel (ECP) redirection fails in Exchange Server 2016
  • 4058384 Get-CalendarDiagnosticAnalysis shows DateTime in 12-hour clock in Exchange Server 2016 and 2013
  • 4058399 Disabling a mailbox can’t remove legacyExchangeDN from user’s properties in Exchange Server 2016
  • 4073094 Emails outside a UID range are returned when you request for emails by using IMAP
  • 4073095 “550 5.6.0 CAT.InvalidContent.Exception” and email isn’t delivered in Exchange Server 2016 and 2013
  • 4073104 PIN can be reset on a Unified Messaging (UM)-enabled mailbox for a user outside a scoped OU
  • 4073103 The Enable-Mailbox cmdlet doesn’t block migrated users from provisioning in Exchange Server 2016
  • 4073107 Language can’t be changed when a user from a child domain tries to change language in OWA
  • 4073111 Can’t access a CAS website such as OWA/ECP/Autodiscover in Exchange Server 2016
  • 4073110 You can’t access OWA or ECP after you install Exchange Server 2016 CU8
  • 4073109 Search-MailboxAuditLog -ShowDetails not showing all messages in Exchange Server 2016
  • 4073114 “ADOperationException” error when OWA text verification fails in Exchange Server 2016
  • 4073214 Can’t enable OWA offline access in Exchange Server 2016
  • 4073531 CultureNotFoundException when selecting a LCID 4096 language in OWA for Exchange Server 2016
  • 4076520 MatchSubdomains isn’t usable for Set-AcceptedDomain in Exchange Server 2016
  • 4076741 Incorrect NDR when an administrator deletes a message from a queue in Exchange Server 2016
  • 4077655 Event ID 258 “Unable to determine the installed file” after you uninstall Windows PowerShell 2.0
  • 4057290 Incorrect user is returned in the ECP when one user’s display name matches another user’s alias
  • 4058372 Blank page in Exchange Admin Center Audit Log in Exchange Server 2016
  • 4058382 Can’t retrieve time slot information about private calendar items as a delegate on another user’s account in Exchange Server 2016
  • 4058401 Administrator audit logging does not record Set-ServerComponentState cmdlet details in Exchange Server 2013 or 2016 environment
  • 4073097 Monitoring probes of ECP.Proxy health checks fail on all CAS roles in Exchange Server 2013 and 2016
  • 4073098 The ETS and EXS groups are incorrectly granted “SeDebugPrivilege” in Exchange Server 2016 on-premises
  • 4073108 “There was a problem loading your options” error when a user accesses OWA Voice Mail options in Exchange Server 2016
  • 4077924 Store Worker process crashes when you move, restore, or repair mailboxes that have issues with the logical index within the database in Exchange Server 2016
  • 4091453 Update improves linguistics features and CJK handling for search in Exchange Server 2016
  • 4073392 Description of the security update for Microsoft Exchange: March 13, 2018

Exchange 2013 CU20 fixes:

  • 4073392 Description of the security update for Microsoft Exchange: March 13, 2018
  • 4073094 Emails outside a UID range are returned when you request for emails by using IMAP
  • 4073097 Monitoring probes of ECP.Proxy health checks fail on all CAS roles in Exchange Server 2013 and 2016
  • 4057216 Health mailbox’s password is exposed in logs for a failed probe in Exchange Server 2016 and 2013
  • 4058384 Get-CalendarDiagnosticAnalysis shows DateTime in 12-hour clock in Exchange Server 2016 and 2013
  • 4057290 Incorrect user is returned in the ECP when one user’s display name matches another user’s alias
  • 4055433 User is added to an entire series when accepting a single instance through Exchange ActiveSync
  • 4058401 Administrator audit logging does not record Set-ServerComponentState cmdlet details in Exchange Server 2013 or 2016 environment
  • 4073095 “550 5.6.0 CAT.InvalidContent.Exception” and email isn’t delivered in Exchange Server 2016 and 2013
  • 4058379 All cross-forest meeting updates have to be accepted again in Exchange Server 2016 and 2013
  • 4073093 Save issues occur when you use the plain Text Editor in OWA of Exchange Server 2013
  • 4073096 Emails sent from a shared mailbox aren’t saved in Sent Items when MessageCopyForSentAsEnabled is True

Notes:

  • Exchange 2016 CU7 and later requires Forest Functionality Level 2008R2 or later.
  • Exchange 2016 CU8 and Exchange 2013 CU18 do not contain schema changes compared to their previous Cumulative Update. However, they may introduce RBAC changes in your environment. Use setup /PrepareSchema to manually update the schema, or use /PrepareAD to apply RBAC changes, before deploying or updating Exchange servers. To see if you need to update the schema compared to your version or verify the update has been performed, consult the Exchange schema overview.
  • When upgrading from an n-2 or earlier version of Exchange, or an early version of the .NET Framework, consult Upgrade Paths for CU’s & .NET.
  • When upgrading your Exchange 2013 or 2016 installation, don’t forget to put the server in maintenance mode when required. Regardless, setup will put the server in server-wide offline mode post-analysis, before making actual changes.
  • Using Windows Management Framework (WMF)/PowerShell version 5 or later on anything earlier than Windows Server 2016 is not supported. Don’t install WMF5 on your Exchange servers running on Windows Server 2012 R2 or earlier.
  • When using Exchange hybrid deployments or Exchange Online Archiving (EOA), you are required to stay at most one version behind (n-1).
  • If you want to speed up the update process for systems without internet access, you can follow the procedure described here to disable publisher’s certificate revocation checking.
  • Cumulative Updates can be installed directly, i.e. no need to install RTM prior to installing Cumulative Updates.
  • Once installed, you can’t uninstall a Cumulative Update nor any of the installed Exchange server roles.
  • The order in which you upgrade servers with Cumulative Updates is irrelevant.

Caution:

As for any update, I recommend to thoroughly test updates in a test environment prior to implementing them in production. When you lack such facilities, hold out a few days and monitor the comments on the original publication or forums for any issues.