URL Added to Application from Unknown Domain

let domains =
  SigninLogs
  | where ResultType == 0
  | extend domain = split(UserPrincipalName, "@")[1]
  | extend domain = tostring(split(UserPrincipalName, "@")[1])
  | summarize by tolower(tostring(domain));
  AuditLogs
  | where Category =~ "ApplicationManagement"
  | where Result =~ "success"
  | where OperationName =~ 'Update Application'
  | mv-expand TargetResources
  | mv-expand TargetResources.modifiedProperties
  | where TargetResources_modifiedProperties.displayName =~ "AppAddress"
  | extend Key = tostring(TargetResources_modifiedProperties.displayName)
  | extend NewValue = TargetResources_modifiedProperties.newValue
  | extend OldValue = TargetResources_modifiedProperties.oldValue
  | where isnotempty(Key) and isnotempty(NewValue)
  | project-reorder Key, NewValue, OldValue
  | extend NewUrls = extract_all('"Address":([^,]*)', tostring(NewValue))
  | extend OldUrls = extract_all('"Address":([^,]*)', tostring(OldValue))
  | extend AddedUrls = set_difference(NewUrls, OldUrls)
  | where array_length(AddedUrls) > 0
  | extend UserAgent = iif(tostring(AdditionalDetails[0].key) == "User-Agent", tostring(AdditionalDetails[0].value), "")
  | extend InitiatingAppName = tostring(InitiatedBy.app.displayName)
  | extend InitiatingAppServicePrincipalId = tostring(InitiatedBy.app.servicePrincipalId)
  | extend InitiatingUserPrincipalName = tostring(InitiatedBy.user.userPrincipalName)
  | extend InitiatingAadUserId = tostring(InitiatedBy.user.id)
  | extend InitiatingIPAddress = tostring(InitiatedBy.user.ipAddress)
  | extend InitiatedBy = tostring(iff(isnotempty(InitiatingUserPrincipalName),InitiatingUserPrincipalName, InitiatingAppName))
  | extend AppDisplayName = tostring(TargetResources.displayName)
  | where isnotempty(AddedUrls)
  | mv-expand AddedUrls
  | extend AddedUrls = trim(@'"', tostring(AddedUrls))
  | extend Domain = extract("^(?:https?:\\/\\/)?(?:[^@\\/\\n]+@)?(?:www\\.)?([^:\\/?\\n]+)/", 1, replace_string(tolower(AddedUrls), '"', ""))
  | where isnotempty(Domain)
  | extend Domain = strcat(split(Domain, ".")[-2], ".", split(Domain, ".")[-1])
  | where Domain !in (domains)
  | project-reorder TimeGenerated, AppDisplayName, AddedUrls, InitiatedBy, UserAgent, InitiatingIPAddress
  | extend InitiatingAccountName = tostring(split(InitiatingUserPrincipalName, "@")[0]), InitiatingAccountUPNSuffix = tostring(split(InitiatingUserPrincipalName, "@")[1])

queryPeriod: 2h
query: |
  let domains =
    SigninLogs
    | where ResultType == 0
    | extend domain = split(UserPrincipalName, "@")[1]
    | extend domain = tostring(split(UserPrincipalName, "@")[1])
    | summarize by tolower(tostring(domain));
    AuditLogs
    | where Category =~ "ApplicationManagement"
    | where Result =~ "success"
    | where OperationName =~ 'Update Application'
    | mv-expand TargetResources
    | mv-expand TargetResources.modifiedProperties
    | where TargetResources_modifiedProperties.displayName =~ "AppAddress"
    | extend Key = tostring(TargetResources_modifiedProperties.displayName)
    | extend NewValue = TargetResources_modifiedProperties.newValue
    | extend OldValue = TargetResources_modifiedProperties.oldValue
    | where isnotempty(Key) and isnotempty(NewValue)
    | project-reorder Key, NewValue, OldValue
    | extend NewUrls = extract_all('"Address":([^,]*)', tostring(NewValue))
    | extend OldUrls = extract_all('"Address":([^,]*)', tostring(OldValue))
    | extend AddedUrls = set_difference(NewUrls, OldUrls)
    | where array_length(AddedUrls) > 0
    | extend UserAgent = iif(tostring(AdditionalDetails[0].key) == "User-Agent", tostring(AdditionalDetails[0].value), "")
    | extend InitiatingAppName = tostring(InitiatedBy.app.displayName)
    | extend InitiatingAppServicePrincipalId = tostring(InitiatedBy.app.servicePrincipalId)
    | extend InitiatingUserPrincipalName = tostring(InitiatedBy.user.userPrincipalName)
    | extend InitiatingAadUserId = tostring(InitiatedBy.user.id)
    | extend InitiatingIPAddress = tostring(InitiatedBy.user.ipAddress)
    | extend InitiatedBy = tostring(iff(isnotempty(InitiatingUserPrincipalName),InitiatingUserPrincipalName, InitiatingAppName))
    | extend AppDisplayName = tostring(TargetResources.displayName)
    | where isnotempty(AddedUrls)
    | mv-expand AddedUrls
    | extend AddedUrls = trim(@'"', tostring(AddedUrls))
    | extend Domain = extract("^(?:https?:\\/\\/)?(?:[^@\\/\\n]+@)?(?:www\\.)?([^:\\/?\\n]+)/", 1, replace_string(tolower(AddedUrls), '"', ""))
    | where isnotempty(Domain)
    | extend Domain = strcat(split(Domain, ".")[-2], ".", split(Domain, ".")[-1])
    | where Domain !in (domains)
    | project-reorder TimeGenerated, AppDisplayName, AddedUrls, InitiatedBy, UserAgent, InitiatingIPAddress
    | extend InitiatingAccountName = tostring(split(InitiatingUserPrincipalName, "@")[0]), InitiatingAccountUPNSuffix = tostring(split(InitiatingUserPrincipalName, "@")[1])  
kind: Scheduled
triggerThreshold: 0
metadata:
  categories:
    domains:
    - Security - Others
  support:
    tier: Community
  source:
    kind: Community
  author:
    name: Microsoft Security Research
requiredDataConnectors:
- dataTypes:
  - AuditLogs
  connectorId: AzureActiveDirectory
description: |
  'Detects a URL being added to an application where the domain is not one that is associated with the tenant.
    The query uses domains seen in sign in logs to determine if the domain is associated with the tenant.
    Applications associated with URLs not controlled by the organization can pose a security risk.
    Ref: https://learn.microsoft.com/en-gb/entra/architecture/security-operations-applications#application-configuration-changes'  
tags:
- AADSecOpsGuide
relevantTechniques:
- T1078.004
tactics:
- Persistence
- PrivilegeEscalation
queryFrequency: 2h
name: URL Added to Application from Unknown Domain
version: 1.1.1
severity: High
id: 017e095a-94d8-430c-a047-e51a11fb737b
triggerOperator: gt
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/URLAddedtoApplicationfromUnknownDomain.yaml
entityMappings:
- entityType: URL
  fieldMappings:
  - identifier: Url
    columnName: AddedUrls
- entityType: Account
  fieldMappings:
  - identifier: Name
    columnName: InitiatingAppName
  - identifier: AadUserId
    columnName: InitiatingAppServicePrincipalId
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: InitiatingUserPrincipalName
  - identifier: Name
    columnName: InitiatingAccountName
  - identifier: UPNSuffix
    columnName: InitiatingAccountUPNSuffix
- entityType: Account
  fieldMappings:
  - identifier: AadUserId
    columnName: InitiatingAadUserId
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: InitiatingIPAddress