TI map Email entity to OfficeActivity
Id | 4a3f5ed7-8da5-4ce2-af6f-c9ada45060f2 |
Rulename | TI map Email entity to OfficeActivity |
Description | Identifies a match in OfficeActivity table from any Email IOC from TI |
Severity | Medium |
Tactics | InitialAccess |
Techniques | T1566 |
Required data connectors | MicrosoftDefenderThreatIntelligence Office365 ThreatIntelligence ThreatIntelligenceTaxii |
Kind | Scheduled |
Query frequency | 1h |
Query period | 14d |
Trigger threshold | 0 |
Trigger operator | gt |
Source Uri | https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/EmailEntity_OfficeActivity.yaml |
Version | 1.2.7 |
Arm template | 4a3f5ed7-8da5-4ce2-af6f-c9ada45060f2.json |
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$';
let OfficeEvents = materialize(
OfficeActivity
| where isnotempty(UserId)
| where TimeGenerated >= ago(dt_lookBack)
| where UserId matches regex emailregex
| project-rename OfficeActivity_TimeGenerated = TimeGenerated);
let OfficeActivityUPNs = OfficeEvents | distinct UserId = tolower(UserId) | summarize make_list(UserId);
ThreatIntelligenceIndicator
| where isnotempty(EmailSenderAddress)
| where TimeGenerated >= ago(ioc_lookBack)
| where tolower(EmailSenderAddress) in (OfficeActivityUPNs)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now()
| where Description !contains_cs "State: inactive;" and Description !contains_cs "State: falsepos;"
// using innerunique to keep perf fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated
| join kind=innerunique (OfficeEvents) on $left.EmailSenderAddress == $right.UserId
| where OfficeActivity_TimeGenerated < ExpirationDateTime
| summarize OfficeActivity_TimeGenerated = arg_max(OfficeActivity_TimeGenerated, *) by IndicatorId, UserId
| project OfficeActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore, EmailSenderName, EmailRecipient, EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType, UserId, ClientIP, Operation, UserType, RecordType, OfficeWorkload, Parameters
| extend Name = tostring(split(UserId, '@', 0)[0]), UPNSuffix = tostring(split(UserId, '@', 1)[0])
| extend timestamp = OfficeActivity_TimeGenerated
entityMappings:
- entityType: Account
fieldMappings:
- identifier: FullName
columnName: UserId
- identifier: Name
columnName: Name
- identifier: UPNSuffix
columnName: UPNSuffix
- entityType: IP
fieldMappings:
- identifier: Address
columnName: ClientIP
- entityType: URL
fieldMappings:
- identifier: Url
columnName: Url
queryFrequency: 1h
name: TI map Email entity to OfficeActivity
severity: Medium
kind: Scheduled
tactics:
- InitialAccess
triggerThreshold: 0
query: |
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$';
let OfficeEvents = materialize(
OfficeActivity
| where isnotempty(UserId)
| where TimeGenerated >= ago(dt_lookBack)
| where UserId matches regex emailregex
| project-rename OfficeActivity_TimeGenerated = TimeGenerated);
let OfficeActivityUPNs = OfficeEvents | distinct UserId = tolower(UserId) | summarize make_list(UserId);
ThreatIntelligenceIndicator
| where isnotempty(EmailSenderAddress)
| where TimeGenerated >= ago(ioc_lookBack)
| where tolower(EmailSenderAddress) in (OfficeActivityUPNs)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now()
| where Description !contains_cs "State: inactive;" and Description !contains_cs "State: falsepos;"
// using innerunique to keep perf fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated
| join kind=innerunique (OfficeEvents) on $left.EmailSenderAddress == $right.UserId
| where OfficeActivity_TimeGenerated < ExpirationDateTime
| summarize OfficeActivity_TimeGenerated = arg_max(OfficeActivity_TimeGenerated, *) by IndicatorId, UserId
| project OfficeActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore, EmailSenderName, EmailRecipient, EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType, UserId, ClientIP, Operation, UserType, RecordType, OfficeWorkload, Parameters
| extend Name = tostring(split(UserId, '@', 0)[0]), UPNSuffix = tostring(split(UserId, '@', 1)[0])
| extend timestamp = OfficeActivity_TimeGenerated
triggerOperator: gt
queryPeriod: 14d
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/EmailEntity_OfficeActivity.yaml
relevantTechniques:
- T1566
id: 4a3f5ed7-8da5-4ce2-af6f-c9ada45060f2
requiredDataConnectors:
- connectorId: Office365
dataTypes:
- OfficeActivity
- connectorId: ThreatIntelligence
dataTypes:
- ThreatIntelligenceIndicator
- connectorId: ThreatIntelligenceTaxii
dataTypes:
- ThreatIntelligenceIndicator
- connectorId: MicrosoftDefenderThreatIntelligence
dataTypes:
- ThreatIntelligenceIndicator
version: 1.2.7
description: |
'Identifies a match in OfficeActivity table from any Email IOC from TI'
{
"$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/4a3f5ed7-8da5-4ce2-af6f-c9ada45060f2')]",
"kind": "Scheduled",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/4a3f5ed7-8da5-4ce2-af6f-c9ada45060f2')]",
"properties": {
"alertRuleTemplateName": "4a3f5ed7-8da5-4ce2-af6f-c9ada45060f2",
"customDetails": null,
"description": "'Identifies a match in OfficeActivity table from any Email IOC from TI'\n",
"displayName": "TI map Email entity to OfficeActivity",
"enabled": true,
"entityMappings": [
{
"entityType": "Account",
"fieldMappings": [
{
"columnName": "UserId",
"identifier": "FullName"
},
{
"columnName": "Name",
"identifier": "Name"
},
{
"columnName": "UPNSuffix",
"identifier": "UPNSuffix"
}
]
},
{
"entityType": "IP",
"fieldMappings": [
{
"columnName": "ClientIP",
"identifier": "Address"
}
]
},
{
"entityType": "URL",
"fieldMappings": [
{
"columnName": "Url",
"identifier": "Url"
}
]
}
],
"OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/EmailEntity_OfficeActivity.yaml",
"query": "let dt_lookBack = 1h;\nlet ioc_lookBack = 14d;\nlet emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\\.[a-zA-Z0-9-.]+$';\nlet OfficeEvents = materialize(\n OfficeActivity\n | where isnotempty(UserId)\n | where TimeGenerated >= ago(dt_lookBack)\n | where UserId matches regex emailregex\n | project-rename OfficeActivity_TimeGenerated = TimeGenerated);\nlet OfficeActivityUPNs = OfficeEvents | distinct UserId = tolower(UserId) | summarize make_list(UserId);\nThreatIntelligenceIndicator\n| where isnotempty(EmailSenderAddress)\n| where TimeGenerated >= ago(ioc_lookBack)\n| where tolower(EmailSenderAddress) in (OfficeActivityUPNs)\n| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId\n| where Active == true and ExpirationDateTime > now()\n| where Description !contains_cs \"State: inactive;\" and Description !contains_cs \"State: falsepos;\"\n// using innerunique to keep perf fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated\n| join kind=innerunique (OfficeEvents) on $left.EmailSenderAddress == $right.UserId\n| where OfficeActivity_TimeGenerated < ExpirationDateTime\n| summarize OfficeActivity_TimeGenerated = arg_max(OfficeActivity_TimeGenerated, *) by IndicatorId, UserId\n| project OfficeActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore, EmailSenderName, EmailRecipient, EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType, UserId, ClientIP, Operation, UserType, RecordType, OfficeWorkload, Parameters\n| extend Name = tostring(split(UserId, '@', 0)[0]), UPNSuffix = tostring(split(UserId, '@', 1)[0])\n| extend timestamp = OfficeActivity_TimeGenerated\n",
"queryFrequency": "PT1H",
"queryPeriod": "P14D",
"severity": "Medium",
"subTechniques": [],
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"InitialAccess"
],
"techniques": [
"T1566"
],
"templateVersion": "1.2.7",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0
},
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
}
]
}