Security Updates Exchange 2013-2019 (Nov2020)

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 CU7Download15.2.721.4KB4588741
Exchange 2019 CU6Download15.2.659.8KB4588741
Exchange 2016 CU18Download15.1.2106.4KB4588741
Exchange 2016 CU17Download15.1.2044.8KB4588741
Exchange 2013 CU23Download15.0.1497.8KB4588741

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 2016-2019 (Sep2020)

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

  • CVE-2020-16875: Exchange Memory Corruption Vulnerability
    A remote code execution vulnerability exists in Microsoft Exchange server due to improper validation of cmdlet arguments. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the System user. Exploitation of the vulnerability requires an authenticated user in a certain Exchange role to be compromised. The security update addresses the vulnerability by correcting how Microsoft Exchange handles cmdlet arguments.

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

ExchangeDownloadBuildKBSupersedes
Exchange 2019 CU6Download15.2.659.6KB4577352KB4540123
Exchange 2019 CU5Download15.2.595.6KB4577352KB4540123
Exchange 2016 CU17Download15.1.2044.6KB4577352KB4540123
Exchange 2016 CU16Download15.1.1979.6KB4577352KB4540123

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-KB4577352-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 2010-2019 (Feb2020)

A quick blog on recently published security updates for Exchange Server 2013 up to Exchange Server 2019 and Exchange Server 2010 as well. These fixes address the following vulnerabilities:

  • CVE-2020-0692: Microsoft Exchange Server Elevation of Privilege Vulnerability

An elevation of privilege vulnerability exists in Microsoft Exchange Server. An attacker who successfully exploited this vulnerability could gain the same rights as any other user of the Exchange server. This could allow the attacker to perform activities such as accessing the mailboxes of other users. Exploitation of this vulnerability requires Exchange Web Services (EWS) to be enabled and in use in an affected environment. To exploit the vulnerability, an attacker would need to change parameters in the Security Access Token and forward it to a Microsoft Exchange Server, thereby allowing impersonation of another Exchange user. To address this vulnerability, Microsoft has changed the way EWS handles these tokens.
This vulnerability does not apply to Exchange 2010.

  • CVE-2020-0688: Microsoft Exchange Memory Corruption Vulnerability

A remote code execution vulnerability exists in Microsoft Exchange Server when the server fails to properly create unique keys at install time. Knowledge of a the validation key allows an authenticated user with a mailbox to pass arbitrary objects to be deserialized by the web application, which runs as SYSTEM. The security update addresses the vulnerability by correcting how Microsoft Exchange creates the keys during install.

The CVE documents contain more details on the vulnerabilities. In addition, KB4536989 (Rollup 30) for Exchange 2010 and KB4536988 for Exchange 2013 also fixes the following issue:

  • KB4540267 MSExchangeDelivery.exe or EdgeTransport.exe crashes in Exchange Server 2013 and Exchange Server 2010

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

ExchangeDownloadBuildKBSupersedes
Exchange 2019 CU4Download15.2.529.8KB4536987KB4523171
Exchange 2019 CU3Download15.2.464.11KB4536987KB4523171
Exchange 2016 CU15Download15.1.1913.7KB4536987KB4523171
Exchange 2016 CU14Download15.1.1847.7KB4536987KB4523171
Exchange 2013 CU23Download15.0.1497.6KB4536988KB4523171
Exchange 2010 SP3 RU30KB4536989KB4509410

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 CU15 to Exchange 2016 CU14. I would suggest tagging the Cumulative Update in the file name used, e.g. Exchange2016-CU15-KB4536987-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 (Nov2019)

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.

Security Updates Exchange 2016 & 2019 (Sep2019)

Today, Microsoft published security fixes for Exchange Server 2016 and 2019. These fixes address the following vulnerabilities:

The CVE documents contain more details on the vulnerabilities. These exploits can be fixed by single security updates; you can download them here:

VersionLinksBuildKB
2019 CU2Download15.2.397.6KB4515832
2019 CU1Download15.2.330.10KB4515832
2016 CU13Download15.1.1779.5KB4515832
2016 CU12Download15.1.1713.9KB4515832

Note: KB4515832 supersedes KB4509409 and KB4509408.

Be advised that these Security Updates are Cumulative Update level specific. Unfortunately, the security update carries the same name for different CU’s, and you cannot apply the same update for Exchange 2016 CU13 to Exchange 2016 CU12. I would suggest tagging the Cumulative Update in the file name when you store it, e.g. Exchange2016-KB4515832-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.

Security Updates Exchange 2010-2019

A quick blog that rather silently, Microsoft published hotfixes for a number of products few days ago, including Exchange Server 2010 up to Exchange Server 2019. These fixes address the following vulnerabilities:

  • CVE-2019-1084: Microsoft Exchange Information Disclosure Vulnerability, allowing non-printable characters to be added to Display Names.
  • CVE-2019-1136: Microsoft Exchange Server Elevation of Privilege Vulnerability, allowing NTLM MITM elevation permissions or impersonation through Exchange Web Services. This sounds like a variation on the NTLM MITM exploit which was fixed earlier this year with the February update cycle.
  • CVE-2019-1137: Microsoft Exchange Server Spoofing Vulnerability, allowing for cross-site scripting (XSS).

The CVE documents contain more details on the vulnerabilities. These exploits can be fixed by single security updates; you can download them here:

VersionCVE
2019
1084
CVE
2019
1136
CVE
2019
1137
DownloadBuildKB
2019 CU2XXLink15.2.397.54509408
2019 CU1XXLink15.2.330.94509408
2016 CU13XXXLink15.1.1779.44509409
2016 CU12XXXLink15.1.1713.84509409
2013 CU23XXXLink15.0.1497.34509409
2010 SP3 RU29XXLink14.3.468.04509410

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.

Security Updates for Spoofing Vulnerability

Ex2013 LogoUpdated April 12th: Notice on KB4487563

Today, as part of patch Tuesday, supported Exchange versions received security updates to remediate the following issues:

Security updates are available for the following product levels, and fix the vulnerability mentioned:

Build KB Download CVE-2019-0817 CVE-2019-0858
Exchange 2019 CU1 15.2.330.7 KB4487563 Download Yes Yes
Exchange 2019 15.2.221.16 KB4487563 Download Yes Yes
Exchange 2016 CU12 15.1.1713.6 KB4487563 Download Yes Yes
Exchange 2016 CU11 15.1.1591.16 KB487563 Download Yes Yes
Exchange 2013 CU22 15.0.1473.4 KB487563 Download Yes Yes
Exchange 2010 SP3 RU27 14.3.452.0 KB4491413 Download Yes No

Notes:

  • CVS-2019-0858 does not apply to Exchange 2010.
  • Exchange 2010 is currently in Extended Support. Extended support for Exchange 2010 ends January 14, 2020.
  • Don’t forget to put the Exchange server in maintenance mode prior to updating.
  • 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.
  • The order of installation shouldn’t matter with the “every server is an island” concept, yet recommended is to upgrade internet-facing first, followed by non-internet-facing servers, and finally Edge Transports.

Notice on KB4487563:
Apart from the known issues mentioned in KB4487563, there are reports the fix terminates while stopping services, and the following error is being logged:
[Error] System.Management.Automation.CommandNotFoundException: The term ‘Stop-SetupService’ is not recognized as the name of a cmdlet, function, script file, or operable program.

This Stop-SetupService isn’t a regular cmdlet, and I assume is an alias created by the update. However, there are reports this operation fails. In those circumstances, next to retrying installation of the update, a workaround might be opening up a PowerShell session and adding the alias yourself using New-Alias Stop-SetupService Stop-Service, followed by running the update. The alias isn’t persistent, so will be gone after you close your session.

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.

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.

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

Ex2013 LogoA quick heads-up as Microsoft released security update for supported releases of Exchange Server 2016.

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

  • CVE-2018-8604: Microsoft Exchange Server Tampering Vulnerability
    A tampering vulnerability exists when Microsoft Exchange Server fails to properly handle profile data. An attacker who successfully exploited this vulnerability could modify a targeted user’s profile data.

You can download the security updates here:

Notes:

  • KB4468741 for Exchange Server 2016 CU10 supersedes KB4459266.

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.