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CONTENTS

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 * (Top)
 * 1History
   Toggle History subsection
   * 1.1Current version
   * 1.2New features
   * 1.3Removed features
 * 2Clustering and high availability
 * 3Licensing
 * 4Clients
   Toggle Clients subsection
   * 4.1Exchange ActiveSync
 * 5Hosted Exchange as a service
   Toggle Hosted Exchange as a service subsection
   * 5.1Third-party providers
   * 5.2Exchange Online
   * 5.3History
 * 6Vulnerabilities and hacks
   Toggle Vulnerabilities and hacks subsection
   * 6.12020
   * 6.22021
   * 6.32023
 * 7See also
 * 8References
 * 9External links

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MICROSOFT EXCHANGE SERVER

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From Wikipedia, the free encyclopedia

Calendaring and mail server



Microsoft Exchange Server
Exchange Server 2019 logo
Developer(s)MicrosoftInitial releaseApril 2, 1996; 27 years
ago (1996-04-02)[1]Stable release2019 RTM (v15.02.221.12) (October 22, 2018; 5
years ago (2018-10-22)) [±][2] Operating systemWindows
ServerPlatformx64TypeCollaborative softwareLicenseProprietary commercial
softwareWebsitewww.microsoft.com/en-us/microsoft-365/exchange/email 

Microsoft Exchange Server is a mail server and calendaring server developed by
Microsoft. It runs exclusively on Windows Server operating systems.

The first version was called Exchange Server 4.0, to position it as the
successor to the related Microsoft Mail 3.5. Exchange initially used the X.400
directory service but switched to Active Directory later. Until version 5.0, it
came bundled with an email client called Microsoft Exchange Client. This was
discontinued in favor of Microsoft Outlook.

Exchange Server primarily uses a proprietary protocol called MAPI to talk to
email clients, but subsequently added support for POP3, IMAP, and EAS. The
standard SMTP protocol is used to communicate to other Internet mail servers.

Exchange Server is licensed both as on-premises software and software as a
service (SaaS). In the on-premises form, customers purchase client access
licenses (CALs); as SaaS, Microsoft charges a monthly service fee instead.


HISTORY[EDIT]

Main article: History of Microsoft Exchange Server

Microsoft had sold a number of simpler email products before, but the first
release of Exchange (Exchange Server 4.0 in April 1996[1]) was an entirely new
X.400-based client–server groupware system with a single database store, which
also supported X.500 directory services. The directory used by Exchange Server
eventually became Microsoft's Active Directory service, an LDAP-compliant
directory service which was integrated into Windows 2000 as the foundation of
Windows Server domains.

As of 2020, there have been ten releases.


CURRENT VERSION[EDIT]

The current version, Exchange Server 2019,[3] was released in October 2018.
Unlike other Office Server 2019 products such as SharePoint and Skype for
Business, Exchange Server 2019 could only be deployed on Windows Server 2019
when it was released. Since Cumulative Update 2022 H1 Exchange 2019 has been
supported on Windows Server 2022.[4] One of the key features of the new release
is that Exchange Server can be deployed onto Windows Server Core for the first
time. Additionally, Microsoft has retired the Unified Messaging feature of
Exchange, meaning that Skype for Business on-premises customers will have to use
alternative solutions for voicemail, such as Azure cloud voicemail.


NEW FEATURES[EDIT]

 * Security: support for installing Exchange Server 2019 onto Windows Server
   Core
 * Performance: supports running Exchange Server with up to 48 processor cores
   and 256 GB of RAM


REMOVED FEATURES[EDIT]

 * Unified Messaging


CLUSTERING AND HIGH AVAILABILITY[EDIT]

Exchange Server Enterprise Edition supports clustering of up to 4 nodes when
using Windows 2000 Server, and up to 8 nodes with Windows Server 2003. Exchange
Server 2003 also introduced active-active clustering, but for two-node clusters
only. In this setup, both servers in the cluster are allowed to be active
simultaneously. This is opposed to Exchange's more common active-passive mode in
which the failover servers in any cluster node cannot be used at all while their
corresponding home servers are active. They must wait, inactive, for the home
servers in the node to fail. Subsequent performance issues with active-active
mode have led Microsoft to recommend that it should no longer be used.[5] In
fact, support for active-active mode clustering has been discontinued with
Exchange Server 2007.

Exchange's clustering (active-active or active-passive mode) has been criticized
because of its requirement for servers in the cluster nodes to share the same
data. The clustering in Exchange Server provides redundancy for Exchange Server
as an application, but not for Exchange data.[6] In this scenario, the data can
be regarded as a single point of failure, despite Microsoft's description of
this set-up as a "Shared Nothing" model.[7] This void has however been filled by
ISVs and storage manufacturers, through "site resilience" solutions, such as
geo-clustering and asynchronous data replication.[8] Exchange Server 2007
introduces new cluster terminology and configurations that address the
shortcomings of the previous "shared data model".[9]

Exchange Server 2007 provides built-in support for asynchronous replication
modeled on SQL Server's "Log shipping"[10] in CCR (Cluster Continuous
Replication) clusters, which are built on MSCS MNS (Microsoft Cluster
Service—Majority Node Set) clusters, which do not require shared storage. This
type of cluster can be inexpensive and deployed in one, or "stretched" across
two data centers for protection against site-wide failures such as natural
disasters. The limitation of CCR clusters is the ability to have only two nodes
and the third node known as "voter node" or file share witness that prevents
"spit in the brain"[11] scenarios, generally hosted as a file share on a Hub
Transport Server. The second type of cluster is the traditional clustering that
was available in previous versions, and is now being referred to as SCC (Single
Copy Cluster). In Exchange Server 2007 deployment of both CCR and SCC clusters
has been simplified and improved; the entire cluster install process takes place
during Exchange Server installation. LCR or Local Continuous Replication has
been referred to as the "poor man's cluster". It is designed to allow for data
replication to an alternative drive attached to the same system and is intended
to provide protection against local storage failures. It does not protect
against the case where the server itself fails.

In November 2007, Microsoft released SP1 for Exchange Server 2007. This service
pack includes an additional high-availability feature called SCR (Standby
Continuous Replication). Unlike CCR, which requires that both servers belong to
a Windows cluster typically residing in the same datacenter, SCR can replicate
data to a non-clustered server, located in a separate datacenter.

With Exchange Server 2010, Microsoft introduced the concept of the Database
Availability Group (DAG). A DAG contains Mailbox servers that become members of
the DAG. Once a Mailbox server is a member of a DAG, the Mailbox Databases on
that server can be copied to other members of the DAG. When a Mailbox server is
added to a DAG, the Failover Clustering Windows role is installed on the server
and all required clustering resources are created.


LICENSING[EDIT]

Like Windows Server products, Exchange Server requires client access licenses,
which are different from Windows CALs. Corporate license agreements, such as the
Enterprise Agreement, or EA, include Exchange Server CALs. It also comes as part
of the Core CAL. Just like Windows Server and other server products from
Microsoft, there is the choice to use User CALs or Device CALs. Device CALs are
assigned to devices (workstation, laptop or PDA), which may be used by one or
more users.[12] User CALs, are assigned to users, allowing them to access
Exchange from any device. User and Device CALs have the same price, however,
they cannot be used interchangeably.

For service providers looking to host Microsoft Exchange, there is a Service
Provider License Agreement (SPLA) available whereby Microsoft receives a monthly
service fee instead of traditional CALs. Two types of Exchange CAL are
available: Exchange CAL Standard and Exchange CAL Enterprise. The Enterprise CAL
is an add-on license to the Standard CAL.


CLIENTS[EDIT]

Microsoft Exchange Server uses a proprietary remote procedure call (RPC)
protocol called MAPI/RPC,[13] which was designed to be used by Microsoft
Outlook. Clients capable of using the proprietary features of Exchange Server
include Evolution,[14] Hiri and Microsoft Outlook. Thunderbird can access
Exchange server via the Owl Plugin.[15]

Exchange Web Services (EWS), an alternative to the MAPI protocol, is a
documented SOAP-based protocol introduced with Exchange Server 2007. Exchange
Web Services is used by the latest version of Microsoft Entourage for Mac and
Microsoft Outlook for Mac - since the release of Mac OS X Snow Leopard Mac
computers running OS X include some support for this technology via Apple's Mail
application.

E-mail hosted on an Exchange Server can also be accessed using POP3, and IMAP4
protocols, using clients such as Windows Live Mail, Mozilla Thunderbird, and
Lotus Notes. These protocols must be enabled on the server. Exchange Server
mailboxes can also be accessed through a web browser, using Outlook Web App
(OWA). Exchange Server 2003 also featured a version of OWA for mobile devices,
called Outlook Mobile Access (OMA).

Microsoft Exchange Server up to version 5.0 came bundled with Microsoft Exchange
Client as the email client. After version 5.0, this was replaced by Microsoft
Outlook, bundled as part of Microsoft Office 97 and later.[16] When Outlook 97
was released, Exchange Client 5.0 was still in development and to be later
released as part of Exchange Server 5.0, primarily because Outlook was only
available for Windows. Later, in Exchange Server 5.5, Exchange Client was
removed and Outlook was made the only Exchange client. As part of Exchange
Server 5.5, Outlook was released for other platforms.

The original Windows 95 "Inbox" client also used MAPI and was called "Microsoft
Exchange". A stripped-down version of the Exchange Client that does not have
support for Exchange Server was released as Windows Messaging to avoid
confusion; it was included with Windows 95 OSR2, Windows 98, and Windows NT 4.
It was discontinued because of the move to email standards such as SMTP, IMAP,
and POP3, all of which Outlook Express supports better than Windows Messaging.


EXCHANGE ACTIVESYNC[EDIT]

Support for Exchange ActiveSync (EAS) was added to Microsoft Exchange Server
2003. It allows a compliant device such as a Windows Mobile device or smartphone
to securely synchronize mail, contacts and other data directly with an Exchange
server and has become a popular mobile access standard for businesses due to
support from companies like Nokia and Apple Inc.[17] as well as its device
security and compliance features.

Support for push email was added to it with Exchange Server 2003 Service Pack 2
and is supported by Windows Phone 7,[18] the iPhone and Android phones,[19] but
notably not for Apple's native Mail app on macOS.

Exchange ActiveSync Policies allow administrators to control which devices can
connect to the organization, remotely deactivate features, and remotely wipe
lost or stolen devices.[20]


HOSTED EXCHANGE AS A SERVICE[EDIT]

Main article: Hosted Exchange

The complexities of managing Exchange Server—namely running both one or more
Exchange Servers, plus Active Directory synchronization servers—make it
attractive for organisations to purchase it as a hosted service.


THIRD-PARTY PROVIDERS[EDIT]

This has been possible from a number of providers[21] for more than 10 years,
but as of June 2018 is that many providers have been marketing the service as
"cloud computing" or "Software-as-a-Service". Exchange hosting allows for
Microsoft Exchange Server to be running in the Internet, also referred to as the
Cloud, and managed by a "Hosted Exchange Server provider" instead of building
and deploying the system in-house.


EXCHANGE ONLINE[EDIT]

Exchange Online is Exchange Server delivered as a cloud service hosted by
Microsoft itself. It is built on the same technologies as on-premises Exchange
Server, and offers essentially the same services as third-party providers which
host Exchange Server instances.[22]

Customers can also choose to combine both on-premises and online options in a
hybrid deployment.[23] Hybrid implementations are popular for organizations that
are unsure of the need or urgency to do a full transition to Exchange Online,
and also allows for staggered email migration.

Hybrid tools can cover the main stack of Microsoft Exchange, Lync, SharePoint,
Windows, and Active Directory servers, in addition to using replica data to
report cloud user experience.[citation needed]


HISTORY[EDIT]

Exchange Online was first provided as a hosted service in dedicated customer
environments in 2005 to select pilot customers.[24] Microsoft launched a
multi-tenant version of Exchange Online as part of the Business Productivity
Online Standard Suite in November 2008.[25] In June 2011, as part of the
commercial release of Microsoft Office 365, Exchange Online was updated with the
capabilities of Exchange Server 2010.

Exchange Server 2010 was developed concurrently as a server product and for the
Exchange Online service.


VULNERABILITIES AND HACKS[EDIT]


2020[EDIT]

In February 2020, an ASP.NET vulnerability was discovered and exploited relying
on a default setting allowing attackers to run arbitrary code with system
privileges, only requiring a connection to the server as well as being logged
into any user account which can be done through credential stuffing.[26][27]

The exploit relied on all versions of Microsoft Exchange using the same static
validation key to decrypt, encrypt, and validate the 'View State' by default on
all installations of the software and all versions of it, where the View State
is used to temporarily preserve changes to an individual page as information is
sent to the server. The default validation key used is therefore public
knowledge, and so when this is used the validation key can be used to decrypt
and falsely verify a modified View State containing commands added by an
attacker.[26][27]

When logged in as any user, any .ASPX page is then loaded, and by requesting
both the session ID of the user login and the correct View State directly from
the server, this correct View State can be deserialised and then modified to
also include arbitrary code and then be falsely verified by the attacker. This
modified View State is then serialised and passed back to the server in a GET
request along with the session ID to show it is from a logged-in user; in
legitimate use, the view state should always be returned in a POST request, and
never a GET request. This combination causes the server to decrypt and run this
added code with its own privileges, allowing the server to be fully compromised
as any command can therefore be run.[26][27]

In July 2020, Positive Technologies published research explaining how hackers
can attack Microsoft Exchange Server without exploiting any vulnerabilities.[28]
It was voted into Top 10 web hacking techniques of 2020 according to PortSwigger
Ltd.[29]


2021[EDIT]

Main article: 2021 Microsoft Exchange Server data breach

In 2021, critical zero-day exploits were discovered in Microsoft Exchange
Server.[30] Thousands of organizations have been affected by hackers using these
techniques to steal information and install malicious code.[31] Microsoft
revealed that these vulnerabilities had existed for around 10 years,[32] but
were exploited only from January 2021 onwards. The attack affected the email
systems of an estimated 250,000 global customers, including state and local
governments, policy think tanks, academic institutions, infectious disease
researchers and businesses such as law firms and defense contractors.[33]

In a separate incident, an ongoing brute-force campaign from mid-2019 to the
present (July 2021)[needs update], attributed by British and American (NSA, FBI,
CISA) security agencies to the GRU, uses/used publicly known Exchange
vulnerabilities, as well as already-obtained account credentials and other
methods, to infiltrate networks and steal data.[34][35]


2023[EDIT]

In September 2023, Microsoft was notified that Microsoft Exchange is vulnerable
to remote code execution including data theft attacks. Microsoft has not fixed
these issues yet.[36]


SEE ALSO[EDIT]

 * History of Microsoft Exchange Server
 * Comparison of mail servers
 * Extensible Storage Engine
 * List of collaborative software
 * Innovative Communications Alliance (Microsoft - Nortel)
 * 2021 Microsoft Exchange Server data breach


REFERENCES[EDIT]

 1.  ^ Jump up to: a b "Microsoft Exchange Server Available". Microsoft. April
     2, 1996. Retrieved February 5, 2023.
 2.  ^ "Exchange Server build numbers and release dates". Microsoft. Retrieved
     February 19, 2018.
 3.  ^ "Microsoft kündigt Exchange 2019 an". September 26, 2017.
 4.  ^ "Released: 2022 H1 Cumulative Updates for Exchange Server".
     TECHCOMMUNITY.MICROSOFT.COM. April 20, 2022. Retrieved April 21, 2022.
 5.  ^ "Considerations when deploying Exchange on an Active/Active cluster".
     Microsoft. Retrieved October 28, 2012.
 6.  ^ "The benefits of Windows 2003 clustering with Exchange 2003". The
     Exchange Team Blog. June 9, 2004. Retrieved October 28, 2012.
 7.  ^ "Exchange Clustering Concepts". TechNet. February 9, 2006. Retrieved
     October 28, 2012.
 8.  ^ "Storage Glossary: Basic Storage Terms". TechNet. Microsoft. March 8,
     2005. Archived from the original on July 15, 2007. Retrieved October 28,
     2012.
 9.  ^ "High availability". TechNet. March 8, 2005. Retrieved July 2, 2007.
 10. ^ "Frequently asked questions—SQL Server 2000—Log shipping". Microsoft.
     March 8, 2005. Retrieved October 28, 2012.
 11. ^ "An update is available that adds a file share witness feature and a
     configurable cluster heartbeats feature to Windows Server 2003 Service Pack
     1-based server clusters". Microsoft. Retrieved October 28, 2012.
 12. ^ "Top 75 Microsoft Licensing Terms – A Glossary From A(ntigen) To Z(une)".
     OMTCO, omt-co Operations Management Technology Consulting GmbH. Retrieved
     April 24, 2013.
 13. ^ "Exchange Server Protocols". Microsoft. November 7, 2008. Retrieved
     October 28, 2012.
 14. ^ "Evolution/FAQ - GNOME Live!". Microsoft. Retrieved October 28, 2012.
 15. ^ Beonex. "Owl for Exchange". Owl for Exchange. Retrieved February 21,
     2020.
 16. ^ "What is the Microsoft Exchange client?".
 17. ^ "Microsoft Exchange ActiveSync Licensees". Microsoft. Retrieved October
     28, 2012.
 18. ^ "Exchange ActiveSync: Frequently Asked Questions". TechNet. Retrieved
     October 28, 2012.
 19. ^ "Exchange ActiveSync". Apple. Retrieved October 28, 2012.
 20. ^ "Apple - iPhone in Business". TechNet. Retrieved October 28, 2012.
 21. ^ "Hosted Exchange Partner Directory". Microsoft. Retrieved October 28,
     2012.
 22. ^ "Microsoft Exchange Online for Enterprises Service Description".
     Microsoft. Retrieved October 28, 2012.
 23. ^ Puca, Anthony (2013). Microsoft Office 365 Administration Inside Out.
     Microsoft Press. pp. 459–462. ISBN 978-0735678231.
 24. ^ Ina Fried (March 10, 2005). "Microsoft hops into managed PC business".
     CNET News. Retrieved October 28, 2012.
 25. ^ "Microsoft hops into managed PC business". Microsoft. November 7, 2008.
     Retrieved October 28, 2012.
 26. ^ Jump up to: a b c "Hackers Scanning for Vulnerable Microsoft Exchange
     Servers, Patch Now!". BleepingComputer. Retrieved March 20, 2021.
 27. ^ Jump up to: a b c Nusbaum, Scott; Response, Christopher Paschen in
     Incident; Response, Incident; Forensics (February 28, 2020). "Detecting
     CVE-2020-0688 Remote Code Execution Vulnerability on Microsoft Exchange
     Server". TrustedSec. Retrieved March 20, 2021.
 28. ^ Sharoglazov, Arseniy (July 23, 2020). "Attacking MS Exchange Web
     Interfaces". PT SWARM. Retrieved June 18, 2022.
 29. ^ "Top 10 web hacking techniques of 2020". PortSwigger Research. February
     24, 2021. Retrieved June 18, 2022.
 30. ^ "HAFNIUM targeting Exchange Servers with 0-day exploits". Microsoft
     Security. March 2, 2021. Retrieved March 14, 2021.
 31. ^ "Exchange email hack: Hundreds of UK firms compromised". BBC News. March
     11, 2021. Retrieved March 12, 2021.
 32. ^ "Microsoft's big email hack: What happened, who did it, and why it
     matters". CNBC. March 9, 2021. Retrieved March 14, 2021.
 33. ^ "Here's what we know so far about the massive Microsoft Exchange hack".
     CNN. March 10, 2021. Retrieved March 14, 2021.
 34. ^ "NSA, Partners Release Cybersecurity Advisory on Brute Force Global Cyber
     Campaign". nsa.gov. National Security Agency. Archived from the original on
     July 2, 2021. Retrieved July 2, 2021.
 35. ^ "Russian GRU Conducting Global Brute Force Campaign to Compromise
     Enterprise and Cloud Environments" (PDF). Defense.gov. Joint publication
     form US/UK security agencies. Retrieved July 3, 2021.
 36. ^ New Microsoft Exchange zero-days allow RCE, data theft attacks


EXTERNAL LINKS[EDIT]

 * Microsoft Exchange Server – official site



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