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 a Domain Administrator.
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 Active Directory domain controller, thereby facilitating gaining of increased privileges on the domain controller.
To address this vulnerability, Microsoft has evaluated the rights granted to Exchange Servers and Exchange Administrators in the identified scenarios and determined changes are possible which lower the permissions granted within an Active Directory domain. The actual permission changes will vary based upon the version of Exchange Server in use. Please see 4490059 for more information.
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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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-2019-0686.
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-2019-0686.
Уязвимость почтового сервера Microsoft Exchange Server, связанная с недостатками контроля доступа, позволяющая нарушителю изменить права доступа к файлам
EPSS