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mvelazco
73 lines
3.7 KiB
YAML
73 lines
3.7 KiB
YAML
name: Azure AD User ImmutableId Attribute Updated
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id: 0c0badad-4536-4a84-a561-5ff760f3c00e
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version: 1
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date: '2022-09-02'
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author: Mauricio Velazco, Splunk
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type: TTP
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datamodel: []
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description: The following analytic identifies the modification of the SourceAnchor (also called ImmutableId) attribute for an Azure Active Directory user. Updating this attribute
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is a step required to set up the Azure Active Directory identity federation backdoor technique discovered by security researcher Nestori Syynimaa.
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Similar to Active Directory, Azure AD uses the concept of domains to manage directories of identities. A new Azure AD tenant will initially contain a
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single domain that is commonly called the `cloud-only` onmicrosoft.com domain. Organizations can also add their registered custom domains to Azure AD for
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email addresses to match the organizations domain name. If the organization intends to use a third-party identity provider such as ADFS for authentication,
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the added custom domains can be configured as federated. An adversary who has obtained privileged access to an Azure AD tenant may leverage this technique
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to establish persistence and be able to authenticate to Azure AD impersonating any user and bypassing the requirement to have a valid password and/or perform MFA.
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search: ' `azuread` body.operationName="Update user" body.properties.targetResources{}.modifiedProperties{}.displayName=SourceAnchor
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| rename body.properties.* as *
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| rename targetResources{}.userPrincipalName as userPrincipalName
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| rename initiatedBy.user.userPrincipalName as initiatedBy
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| rename body.callerIpAddress as callerIpAddress
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| rename targetResources{}.modifiedProperties{}.newValue as modifiedProperties
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| stats values(userPrincipalName) values(modifiedProperties) by _time, initiatedBy, callerIpAddress, result, body.operationName
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| `azure_ad_user_immutableid_attribute_updated_filter`'
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how_to_implement: You must install the latest version of Splunk Add-on for Microsoft Cloud Services from Splunkbase(https://splunkbase.splunk.com/app/3110/#/details). You must be ingesting Azure Active Directory events into your Splunk environment.
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Specifically, this analytic leverages the AuditLogs log category.
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known_false_positives: The SourceAnchor (also called ImmutableId) Azure AD attribute has legitimate uses for directory synchronization. Investigate and filter as needed.
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references:
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- https://docs.microsoft.com/en-us/azure/active-directory/hybrid/plan-connect-design-concepts
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- https://www.mandiant.com/resources/remediation-and-hardening-strategies-microsoft-365-defend-against-apt29-v13
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- https://o365blog.com/post/federation-vulnerability/
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- https://www.inversecos.com/2021/11/how-to-detect-azure-active-directory.html
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- https://www.mandiant.com/resources/blog/detecting-microsoft-365-azure-active-directory-backdoors
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- https://attack.mitre.org/techniques/T1098/
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tags:
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analytic_story:
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- Azure Active Directory Persistence
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asset_type: Azure Active Directory
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cis20:
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- CIS 3
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- CIS 5
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- CIS 16
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confidence: 90
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context:
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- Source:Cloud Data
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- Stage:Persistence
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dataset:
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- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1098/azure_ad_set_immutableid/azure-audit.log
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impact: 50
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kill_chain_phases:
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- Installation
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- Actions on Objectives
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message: The SourceAnchor or ImmutableID attribute has been modified for user $userPrincipalName$ by $initiatedBy$
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mitre_attack_id:
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- T1098
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nist:
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- DE.CM
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observable:
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- name: userPrincipalName
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type: User
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role:
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- Victim
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- name: initiatedBy
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type: User
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role:
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- Attacker
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product:
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- Splunk Enterprise
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- Splunk Enterprise Security
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- Splunk Cloud
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required_fields:
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- _time
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risk_score: 45
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security_domain: threat
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