Guest Users Invited to Tenant by New Inviters
| Id | 572e75ef-5147-49d9-9d65-13f2ed1e3a86 |
| Rulename | Guest Users Invited to Tenant by New Inviters |
| Description | Detects when a Guest User is added by a user account that has not been seen adding a guest in the previous 14 days. Monitoring guest accounts and the access they are provided is important to detect potential account abuse. Accounts added should be investigated to ensure the activity was legitimate. Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-user-accounts#monitoring-for-failed-unusual-sign-ins |
| Severity | Medium |
| Tactics | Persistence |
| Techniques | T1078.004 |
| Required data connectors | AzureActiveDirectory |
| Kind | Scheduled |
| Query frequency | 1d |
| Query period | 14d |
| Trigger threshold | 0 |
| Trigger operator | gt |
| Source Uri | https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/GuestUsersInvitedtoTenantbyNewInviters.yaml |
| Version | 1.1.1 |
| Arm template | 572e75ef-5147-49d9-9d65-13f2ed1e3a86.json |
let inviting_users = (AuditLogs
| where TimeGenerated between(ago(14d)..ago(1d))
| where OperationName =~ "Invite external user"
| where Result =~ "success"
| extend InitiatingUserPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)
| where isnotempty(InitiatingUserPrincipalName)
| summarize by InitiatingUserPrincipalName);
AuditLogs
| where TimeGenerated > ago(1d)
| where OperationName =~ "Invite external user"
| where Result =~ "success"
| extend InitiatingUserPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)
| extend InitiatingAadUserId = tostring(InitiatedBy.user.id)
| extend InitiatingIPAddress = tostring(InitiatedBy.user.ipAddress)
| where isnotempty(InitiatingUserPrincipalName) and InitiatingUserPrincipalName !in (inviting_users)
| extend TargetUserPrincipalName = tostring(TargetResources[0].userPrincipalName)
| extend TargetAadUserId = tostring(TargetResources[0].id)
| extend invitingUser = InitiatingUserPrincipalName, invitedUserPrincipalName = TargetUserPrincipalName
| extend InitiatingAccountName = tostring(split(InitiatingUserPrincipalName, "@")[0]), InitiatingAccountUPNSuffix = tostring(split(InitiatingUserPrincipalName, "@")[1])
| extend TargetAccountName = tostring(split(TargetUserPrincipalName, "@")[0]), TargetAccountUPNSuffix = tostring(split(TargetUserPrincipalName, "@")[1])
| project-reorder TimeGenerated, OperationName, Result, TargetUserPrincipalName, TargetAadUserId, InitiatingUserPrincipalName, InitiatingAadUserId, InitiatingIPAddress
triggerOperator: gt
triggerThreshold: 0
name: Guest Users Invited to Tenant by New Inviters
metadata:
support:
tier: Community
categories:
domains:
- Security - Others
- Identity
source:
kind: Community
author:
name: Microsoft Security Research
queryPeriod: 14d
severity: Medium
tags:
- AADSecOpsGuide
kind: Scheduled
entityMappings:
- entityType: Account
fieldMappings:
- columnName: InitiatingUserPrincipalName
identifier: FullName
- columnName: InitiatingAccountName
identifier: Name
- columnName: InitiatingAccountUPNSuffix
identifier: UPNSuffix
- entityType: Account
fieldMappings:
- columnName: TargetUserPrincipalName
identifier: FullName
- columnName: TargetAccountName
identifier: Name
- columnName: TargetAccountUPNSuffix
identifier: UPNSuffix
- entityType: Account
fieldMappings:
- columnName: InitiatingAadUserId
identifier: AadUserId
- entityType: Account
fieldMappings:
- columnName: TargetAadUserId
identifier: AadUserId
- entityType: IP
fieldMappings:
- columnName: InitiatingIPAddress
identifier: Address
queryFrequency: 1d
relevantTechniques:
- T1078.004
requiredDataConnectors:
- dataTypes:
- AuditLogs
connectorId: AzureActiveDirectory
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/GuestUsersInvitedtoTenantbyNewInviters.yaml
description: |
'Detects when a Guest User is added by a user account that has not been seen adding a guest in the previous 14 days.
Monitoring guest accounts and the access they are provided is important to detect potential account abuse.
Accounts added should be investigated to ensure the activity was legitimate.
Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-user-accounts#monitoring-for-failed-unusual-sign-ins'
tactics:
- Persistence
query: |
let inviting_users = (AuditLogs
| where TimeGenerated between(ago(14d)..ago(1d))
| where OperationName =~ "Invite external user"
| where Result =~ "success"
| extend InitiatingUserPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)
| where isnotempty(InitiatingUserPrincipalName)
| summarize by InitiatingUserPrincipalName);
AuditLogs
| where TimeGenerated > ago(1d)
| where OperationName =~ "Invite external user"
| where Result =~ "success"
| extend InitiatingUserPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)
| extend InitiatingAadUserId = tostring(InitiatedBy.user.id)
| extend InitiatingIPAddress = tostring(InitiatedBy.user.ipAddress)
| where isnotempty(InitiatingUserPrincipalName) and InitiatingUserPrincipalName !in (inviting_users)
| extend TargetUserPrincipalName = tostring(TargetResources[0].userPrincipalName)
| extend TargetAadUserId = tostring(TargetResources[0].id)
| extend invitingUser = InitiatingUserPrincipalName, invitedUserPrincipalName = TargetUserPrincipalName
| extend InitiatingAccountName = tostring(split(InitiatingUserPrincipalName, "@")[0]), InitiatingAccountUPNSuffix = tostring(split(InitiatingUserPrincipalName, "@")[1])
| extend TargetAccountName = tostring(split(TargetUserPrincipalName, "@")[0]), TargetAccountUPNSuffix = tostring(split(TargetUserPrincipalName, "@")[1])
| project-reorder TimeGenerated, OperationName, Result, TargetUserPrincipalName, TargetAadUserId, InitiatingUserPrincipalName, InitiatingAadUserId, InitiatingIPAddress
id: 572e75ef-5147-49d9-9d65-13f2ed1e3a86
version: 1.1.1
{
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"workspace": {
"type": "String"
}
},
"resources": [
{
"apiVersion": "2024-01-01-preview",
"id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/572e75ef-5147-49d9-9d65-13f2ed1e3a86')]",
"kind": "Scheduled",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/572e75ef-5147-49d9-9d65-13f2ed1e3a86')]",
"properties": {
"alertRuleTemplateName": "572e75ef-5147-49d9-9d65-13f2ed1e3a86",
"customDetails": null,
"description": "'Detects when a Guest User is added by a user account that has not been seen adding a guest in the previous 14 days.\n Monitoring guest accounts and the access they are provided is important to detect potential account abuse.\n Accounts added should be investigated to ensure the activity was legitimate.\n Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-user-accounts#monitoring-for-failed-unusual-sign-ins'\n",
"displayName": "Guest Users Invited to Tenant by New Inviters",
"enabled": true,
"entityMappings": [
{
"entityType": "Account",
"fieldMappings": [
{
"columnName": "InitiatingUserPrincipalName",
"identifier": "FullName"
},
{
"columnName": "InitiatingAccountName",
"identifier": "Name"
},
{
"columnName": "InitiatingAccountUPNSuffix",
"identifier": "UPNSuffix"
}
]
},
{
"entityType": "Account",
"fieldMappings": [
{
"columnName": "TargetUserPrincipalName",
"identifier": "FullName"
},
{
"columnName": "TargetAccountName",
"identifier": "Name"
},
{
"columnName": "TargetAccountUPNSuffix",
"identifier": "UPNSuffix"
}
]
},
{
"entityType": "Account",
"fieldMappings": [
{
"columnName": "InitiatingAadUserId",
"identifier": "AadUserId"
}
]
},
{
"entityType": "Account",
"fieldMappings": [
{
"columnName": "TargetAadUserId",
"identifier": "AadUserId"
}
]
},
{
"entityType": "IP",
"fieldMappings": [
{
"columnName": "InitiatingIPAddress",
"identifier": "Address"
}
]
}
],
"OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/GuestUsersInvitedtoTenantbyNewInviters.yaml",
"query": "let inviting_users = (AuditLogs\n | where TimeGenerated between(ago(14d)..ago(1d))\n | where OperationName =~ \"Invite external user\"\n | where Result =~ \"success\"\n | extend InitiatingUserPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)\n | where isnotempty(InitiatingUserPrincipalName)\n | summarize by InitiatingUserPrincipalName);\n AuditLogs\n | where TimeGenerated > ago(1d)\n | where OperationName =~ \"Invite external user\"\n | where Result =~ \"success\"\n | extend InitiatingUserPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)\n | extend InitiatingAadUserId = tostring(InitiatedBy.user.id)\n | extend InitiatingIPAddress = tostring(InitiatedBy.user.ipAddress)\n | where isnotempty(InitiatingUserPrincipalName) and InitiatingUserPrincipalName !in (inviting_users)\n | extend TargetUserPrincipalName = tostring(TargetResources[0].userPrincipalName)\n | extend TargetAadUserId = tostring(TargetResources[0].id)\n | extend invitingUser = InitiatingUserPrincipalName, invitedUserPrincipalName = TargetUserPrincipalName\n | extend InitiatingAccountName = tostring(split(InitiatingUserPrincipalName, \"@\")[0]), InitiatingAccountUPNSuffix = tostring(split(InitiatingUserPrincipalName, \"@\")[1])\n | extend TargetAccountName = tostring(split(TargetUserPrincipalName, \"@\")[0]), TargetAccountUPNSuffix = tostring(split(TargetUserPrincipalName, \"@\")[1])\n | project-reorder TimeGenerated, OperationName, Result, TargetUserPrincipalName, TargetAadUserId, InitiatingUserPrincipalName, InitiatingAadUserId, InitiatingIPAddress\n",
"queryFrequency": "P1D",
"queryPeriod": "P14D",
"severity": "Medium",
"subTechniques": [
"T1078.004"
],
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"Persistence"
],
"tags": [
"AADSecOpsGuide"
],
"techniques": [
"T1078"
],
"templateVersion": "1.1.1",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0
},
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
}
]
}