mirror of
https://github.com/splunk/security_content
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Bhavin Patel
78 lines
3.8 KiB
YAML
78 lines
3.8 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, Gowthamaraj Rajendran, Splunk
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status: production
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type: TTP
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description: The following analytic identifies the modification of the SourceAnchor
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(also called ImmutableId) attribute for an Azure Active Directory user. Updating
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this attribute is a step required to set up the Azure Active Directory identity
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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
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of identities. A new Azure AD tenant will initially contain a single domain that
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is commonly called the `cloud-only` onmicrosoft.com domain. Organizations can also
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add their registered custom domains to Azure AD for email addresses to match the
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organizations domain name. If the organization intends to use a third-party identity
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provider such as ADFS for authentication, the added custom domains can be configured
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as federated. An adversary who has obtained privileged access to an Azure AD tenant
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may leverage this technique to establish persistence and be able to authenticate
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to Azure AD impersonating any user and bypassing the requirement to have a valid
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password and/or perform MFA.
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data_source: []
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search: ' `azure_monitor_aad` operationName="Update user" properties.targetResources{}.modifiedProperties{}.displayName=SourceAnchor
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| rename properties.* as *
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| rename initiatedBy.user.userPrincipalName as initiatedBy
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| rename targetResources{}.modifiedProperties{}.newValue as modifiedProperties
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| stats count min(_time) as firstTime max(_time) as lastTime values(user) as user values(modifiedProperties) as modifiedProperties by initiatedBy, src_ip, result, operationName
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| `security_content_ctime(firstTime)`
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| `security_content_ctime(lastTime)`
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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
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Cloud Services from Splunkbase(https://splunkbase.splunk.com/app/3110/#/details).
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You must be ingesting Azure Active Directory events into your Splunk environment.
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This analytic was written to be used with the azure:monitor:aad sourcetype leveraging the AuditLog log category.
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known_false_positives: The SourceAnchor (also called ImmutableId) Azure AD attribute
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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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confidence: 90
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impact: 50
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message: The SourceAnchor or ImmutableID attribute has been modified for user $user$
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by $initiatedBy$
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mitre_attack_id:
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- T1098
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observable:
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- name: user
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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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tests:
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- name: True Positive Test
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attack_data:
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- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1098/azure_ad_set_immutableid/azure-audit.log
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source: Azure AD
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sourcetype: azure:monitor:aad
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update_timestamp: true
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