Внедрение в sIDHistory
The Windows security identifier (SID) is a unique value that identifies a user or group account. SIDs are used by Windows security in both security descriptors and access tokens. (Citation: Microsoft SID) An account can hold additional SIDs in the SID-History Active Directory attribute (Citation: Microsoft SID-History Attribute), allowing inter-operable account migration between domains (e.g., all values in SID-History are included in access tokens). Adversaries may use this mechanism for privilege escalation. With Domain Administrator (or equivalent) rights, harvested or well-known SID values (Citation: Microsoft Well Known SIDs Jun 2017) may be inserted into SID-History to enable impersonation of arbitrary users/groups such as Enterprise Administrators. This manipulation may result in elevated access to local resources and/or access to otherwise inaccessible domains via lateral movement techniques such as Remote Services, Windows Admin Shares, or Windows Remote Management.
Контрмеры |
|
Контрмера | Описание |
---|---|
Active Directory Configuration |
Configure Active Directory to prevent use of certain techniques; use SID Filtering, etc. |
SID-History Injection Mitigation |
Clean up SID-History attributes after legitimate account migration is complete.
Consider applying SID Filtering to interforest trusts, such as forest trusts and external trusts, to exclude SID-History from requests to access domain resources. SID Filtering ensures that any authentication requests over a trust only contain SIDs of security principals from the trusted domain (i.e. preventing the trusted domain from claiming a user has membership in groups outside of the domain).
SID Filtering of forest trusts is enabled by default, but may have been disabled in some cases to allow a child domain to transitively access forest trusts. SID Filtering of external trusts is automatically enabled on all created external trusts using Server 2003 or later domain controllers. (Citation: Microsoft Trust Considerations Nov 2014) (Citation: Microsoft SID Filtering Quarantining Jan 2009) However note that SID Filtering is not automatically applied to legacy trusts or may have been deliberately disabled to allow inter-domain access to resources.
SID Filtering can be applied by: (Citation: Microsoft Netdom Trust Sept 2012)
* Disabling SIDHistory on forest trusts using the netdom tool ( |
Обнаружение
Examine data in user’s SID-History attributes using the PowerShell Get-ADUser Cmdlet (Citation: Microsoft Get-ADUser), especially users who have SID-History values from the same domain. (Citation: AdSecurity SID History Sept 2015)
Monitor Account Management events on Domain Controllers for successful and failed changes to SID-History. (Citation: AdSecurity SID History Sept 2015) (Citation: Microsoft DsAddSidHistory)
Monitor Windows API calls to the DsAddSidHistory
function. (Citation: Microsoft DsAddSidHistory)
Ссылки
- Microsoft. (n.d.). Using DsAddSidHistory. Retrieved November 30, 2017.
- Metcalf, S. (2015, September 19). Sneaky Active Directory Persistence #14: SID History. Retrieved November 30, 2017.
- Microsoft. (n.d.). Active Directory Cmdlets - Get-ADUser. Retrieved November 30, 2017.
- Microsoft. (2017, June 23). Well-known security identifiers in Windows operating systems. Retrieved November 30, 2017.
- Microsoft. (n.d.). Active Directory Schema - SID-History attribute. Retrieved November 30, 2017.
- Microsoft. (n.d.). Security Identifiers. Retrieved November 30, 2017.
- Metcalf, S. (2015, August 7). Kerberos Golden Tickets are Now More Golden. Retrieved December 1, 2017.
- Microsoft. (2012, September 11). Command-Line Reference - Netdom Trust. Retrieved November 30, 2017.
- Microsoft. (n.d.). Configuring SID Filter Quarantining on External Trusts. Retrieved November 30, 2017.
- Microsoft. (2014, November 19). Security Considerations for Trusts. Retrieved November 30, 2017.
Связанные риски
Каталоги
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