MaliciousOAuthApp_O365AttackToolkit.yaml

id: f948a32f-226c-4116-bddd-d95e91d97eb9
name: Suspicious application consent similar to O365 Attack Toolkit
description: |
  'This will alert when a user consents to provide a previously-unknown Azure application with the same OAuth permissions used by the MDSec O365 Attack Toolkit (https://github.com/mdsecactivebreach/o365-attack-toolkit).
  The default permissions/scope for the MDSec O365 Attack toolkit change sometimes but often include contacts.read, user.read, mail.read, notes.read.all, mailboxsettings.readwrite, files.readwrite.all, mail.send, files.read, and files.read.all.
  Consent to applications with these permissions should be rare, especially as the knownApplications list is expanded, especially as the knownApplications list is expanded. Public contributions to expand this filter are welcome!
  For further information on AuditLogs please see https://docs.microsoft.com/azure/active-directory/reports-monitoring/reference-audit-activities.'
severity: High
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
      - AuditLogs
queryFrequency: 1d
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
status: Available
tactics:
  - CredentialAccess
  - DefenseEvasion
relevantTechniques:
  - T1528
  - T1550
query: |
  let detectionTime = 1d;
  let joinLookback = 14d;
  let threshold = 5;
  let o365_attack_regex = "contacts.read|user.read|mail.read|notes.read.all|mailboxsettings.readwrite|Files.ReadWrite.All|mail.send|files.read|files.read.all";
  let o365_attack = dynamic(["contacts.read", "user.read", "mail.read", "notes.read.all", "mailboxsettings.readwrite", "Files.ReadWrite.All", "mail.send", "files.read", "files.read.all"]);
  AuditLogs
  | where TimeGenerated > ago(detectionTime)
  | where LoggedByService =~ "Core Directory"
  | where Category =~ "ApplicationManagement"
  | where OperationName =~ "Consent to application"
  | mv-apply TargetResource = TargetResources on 
    (
        where TargetResource.type =~ "ServicePrincipal"
        | extend AppDisplayName = tostring(TargetResource.displayName),
                 AppClientId = tostring(TargetResource.id),
                 props = TargetResource.modifiedProperties
    )
  | where AppClientId !in ((externaldata(knownAppClientId:string, knownAppDisplayName:string)[@"https://raw.githubusercontent.com/Azure/Azure-Sentinel/master/Sample%20Data/Feeds/Microsoft.OAuth.KnownApplications.csv"] with (format="csv"))) // NOTE: a MATCH from this list will cause the alert to NOT fire - please modify for your environment!
  | mv-apply ConsentFull = props on 
    (
        where ConsentFull.displayName =~ "ConsentAction.Permissions"
    )
  | parse ConsentFull with * "ConsentType: " GrantConsentType ", Scope: " GrantScope1 ", CreatedDateTime" * "]" *
  | where GrantConsentType != "AllPrincipals" // NOTE: we are ignoring if OAuth application was granted to all users via an admin - but admin due diligence should be audited occasionally
  | where ConsentFull has_any (o365_attack)  
  | extend GrantScopeCount = countof(tolower(GrantScope1), o365_attack_regex, 'regex')
  | where GrantScopeCount > threshold
  | extend GrantInitiatedByAppName = tostring(InitiatedBy.app.displayName)
  | extend GrantInitiatedByAppServicePrincipalId = tostring(InitiatedBy.app.servicePrincipalId)
  | extend GrantInitiatedByUserPrincipalName = tostring(InitiatedBy.user.userPrincipalName)
  | extend GrantInitiatedByAadUserId = tostring(InitiatedBy.user.id)
  | extend GrantIpAddress = iff(isnotempty(InitiatedBy.user.ipAddress), tostring(InitiatedBy.user.ipAddress), tostring(InitiatedBy.app.ipAddress))
  | extend GrantInitiatedBy = iff(isnotempty(GrantInitiatedByUserPrincipalName), GrantInitiatedByUserPrincipalName, GrantInitiatedByAppName)
  | mv-apply AdditionalDetail = AdditionalDetails on 
    (
        where AdditionalDetail.key =~ "User-Agent"
        | extend GrantUserAgent = AdditionalDetail.value
    )
  | project TimeGenerated, GrantConsentType, GrantScope1, GrantInitiatedBy, AppDisplayName, GrantInitiatedByUserPrincipalName, GrantInitiatedByAadUserId, GrantInitiatedByAppName, GrantInitiatedByAppServicePrincipalId, GrantIpAddress, GrantUserAgent, AppClientId, OperationName, ConsentFull, CorrelationId
  | join kind = leftouter (AuditLogs
    | where TimeGenerated > ago(joinLookback)
    | where LoggedByService =~ "Core Directory"
    | where Category =~ "ApplicationManagement"
    | where OperationName =~ "Add service principal"
    | mv-apply TargetResource = TargetResources on 
        (
            where TargetResource.type =~ "ServicePrincipal"
            | extend props = TargetResource.modifiedProperties,
                    AppClientId = tostring(TargetResource.id)
        )
    | mv-apply Property = props on 
        (
            where Property.displayName =~ "AppAddress" and Property.newValue has "AddressType"
            | extend AppReplyURLs = trim('"',tostring(Property.newValue))
        )
    | distinct AppClientId, tostring(AppReplyURLs)
  ) on AppClientId
  | join kind = innerunique (AuditLogs
        | where TimeGenerated > ago(joinLookback)
        | where LoggedByService =~ "Core Directory"
        | where Category =~ "ApplicationManagement"
        | where OperationName =~ "Add OAuth2PermissionGrant" or OperationName =~ "Add delegated permission grant"
            | mv-apply TargetResource = TargetResources on 
            (
                where TargetResource.type =~ "ServicePrincipal" and array_length(TargetResource.modifiedProperties) > 0 and isnotnull(TargetResource.displayName)
                | extend GrantAuthentication = tostring(TargetResource.displayName)
            )
        | extend GrantOperation = OperationName
        | project GrantAuthentication, GrantOperation, CorrelationId
    ) on CorrelationId
  | project TimeGenerated, GrantConsentType, GrantScope1, GrantInitiatedBy, AppDisplayName, AppReplyURLs, GrantInitiatedByUserPrincipalName, GrantInitiatedByAadUserId, GrantInitiatedByAppName, GrantInitiatedByAppServicePrincipalId, GrantIpAddress, GrantUserAgent, AppClientId, GrantAuthentication, OperationName, GrantOperation, CorrelationId, ConsentFull
  | extend Name = tostring(split(GrantInitiatedByUserPrincipalName,'@',0)[0]), UPNSuffix = tostring(split(GrantInitiatedByUserPrincipalName,'@',1)[0])
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: GrantInitiatedByUserPrincipalName
      - identifier: Name
        columnName: Name
      - identifier: UPNSuffix
        columnName: UPNSuffix
  - entityType: Account
    fieldMappings:
      - identifier: AadUserId
        columnName: GrantInitiatedByAadUserId
  - entityType: Account
    fieldMappings:
      - identifier: AadUserId
        columnName: GrantInitiatedByAppServicePrincipalId
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: GrantIpAddress
  - entityType: CloudApplication
    fieldMappings:
      - identifier: Name
        columnName: AppDisplayName
version: 1.1.2
kind: Scheduled