Описание
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) and Push Notifications to be enabled and in use in an affected environment. To exploit the vulnerability, an attacker would need to execute a man-in-the-middle attack to forward an authentication request to a Microsoft Exchange Server, thereby allowing impersonation of another Exchange user.
To address this vulnerability, Microsoft has changed the notifications contract established between EWS clients and Exchange Servers to not allow authenticated notifications to be streamed by the server. Instead, these notifications will be streamed using anonymous authentication mechanisms.
Меры по смягчению последствий
To address this vulnerability, a Throttling Policy for EWSMaxSubscriptions could be defined and applied to the organization with a value of zero. This will prevent the Exchange server from sending EWS notifications, and prevent client applications which rely upon EWS notifications from functioning normally. Examples of impacted applications include Outlook for Mac, Skype for Business, notification reliant LOB applications, and some iOS native mail clients.
Please see Throttling Policy, for more information.
An example:
New-ThrottlingPolicy -Name AllUsersEWSSubscriptionBlockPolicy -EwsMaxSubscriptions 0 -ThrottlingPolicyScope Organization
A planned update is in development. If you determine that your system is at high risk then you should evaluate the proposed workaround.
After installing the update, you can undo the above action with this command:
Remove-ThrottlingPolicy AllUsersEWSSubscriptionBlockPolicy
FAQ
Is this update related to Microsoft Security Advisory ADV190007?
The update associated with CVE-2019-0686 and CVE-2019-0724 resolve the vulnerability discussed in Microsoft Security Advisory ADV190007. Customers who have implemented the workaround listed in the Security Advisory are encouraged to remove it after applying this update to fully restore previous functionality.
Обновления
| Продукт | Статья | Обновление |
|---|---|---|
| Microsoft Exchange Server 2010 Service Pack 3 Update Rollup 26 | ||
| Microsoft Exchange Server 2013 Cumulative Update 22 | ||
| Microsoft Exchange Server 2016 Cumulative Update 12 | ||
| Microsoft Exchange Server 2019 Cumulative Update 1 | - |
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Возможность эксплуатации
Publicly Disclosed
Exploited
Latest Software Release
Older Software Release
EPSS
Связанные уязвимости
An elevation of privilege vulnerability exists in Microsoft Exchange Server, aka 'Microsoft Exchange Server Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2019-0724.
An elevation of privilege vulnerability exists in Microsoft Exchange Server, aka 'Microsoft Exchange Server Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2019-0724.
Уязвимость почтового сервера Microsoft Exchange Server, связанная с недостатками контроля доступа, позволяющая нарушителю получить доступ к защищаемой информации или изменить права доступа к файлам
EPSS