TI map Domain entity to DnsEvents
Id | 85aca4d1-5d15-4001-abd9-acb86ca1786a |
Rulename | TI map Domain entity to DnsEvents |
Description | Identifies a match in DnsEvents from any Domain IOC from TI |
Severity | Medium |
Tactics | CommandAndControl |
Techniques | T1071 |
Required data connectors | DNS MicrosoftDefenderThreatIntelligence 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/DomainEntity_DnsEvents.yaml |
Version | 1.4.3 |
Arm template | 85aca4d1-5d15-4001-abd9-acb86ca1786a.json |
// Define the lookback periods for time-based filters
let dt_lookBack = 1h; // Look back 1 hour for DNS events
let ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators
// Fetch threat intelligence indicators related to domains
let Domain_Indicators = ThreatIntelligenceIndicator
// Filter out indicators without domain names
| where isnotempty(DomainName)
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now()
| extend TI_DomainEntity = DomainName;
// Create a list of TLDs in our threat feed for later validation
let maxListSize = 100000; // Define the maximum allowed size for each list
let list_tlds = Domain_Indicators
| extend parts = split(DomainName, '.')
| extend tld = parts[(array_length(parts)-1)]
| summarize count() by tostring(tld)
| project tld
| summarize make_list(tld, maxListSize);
// Perform a join between domain indicators and DNS events to identify potential malicious activity
Domain_Indicators
// Use innerunique to keep performance fast and result set low, as we only need one match to indicate potential malicious activity that needs investigation
| join kind=innerunique (
DnsEvents
| where TimeGenerated > ago(dt_lookBack)
// Extract domain patterns from syslog message
| where isnotempty(Name)
| extend parts = split(Name, '.')
| extend tld = parts[(array_length(parts)-1)]
// Validate parsed domain by checking if the TLD is in the list of TLDs in our threat feed
| where tld in~ (list_tlds)
| extend DNS_TimeGenerated = TimeGenerated
) on $left.TI_DomainEntity==$right.Name
// Filter out DNS events that occurred after the expiration of the corresponding indicator
| where DNS_TimeGenerated < ExpirationDateTime
// Group the results by IndicatorId and Name, and keep the DNS event with the latest timestamp
| summarize DNS_TimeGenerated = arg_max(DNS_TimeGenerated, *) by IndicatorId, Name
// Select the desired output fields
| project DNS_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, Url, Computer, ClientIP, Name, QueryType, Type, TI_DomainEntity
// Extract hostname and DNS domain from the Computer field
| extend HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))
// Rename the timestamp field
| extend timestamp = DNS_TimeGenerated
queryFrequency: 1h
description: |
Identifies a match in DnsEvents from any Domain IOC from TI
severity: Medium
version: 1.4.3
relevantTechniques:
- T1071
name: TI map Domain entity to DnsEvents
triggerThreshold: 0
kind: Scheduled
query: |
// Define the lookback periods for time-based filters
let dt_lookBack = 1h; // Look back 1 hour for DNS events
let ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators
// Fetch threat intelligence indicators related to domains
let Domain_Indicators = ThreatIntelligenceIndicator
// Filter out indicators without domain names
| where isnotempty(DomainName)
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now()
| extend TI_DomainEntity = DomainName;
// Create a list of TLDs in our threat feed for later validation
let maxListSize = 100000; // Define the maximum allowed size for each list
let list_tlds = Domain_Indicators
| extend parts = split(DomainName, '.')
| extend tld = parts[(array_length(parts)-1)]
| summarize count() by tostring(tld)
| project tld
| summarize make_list(tld, maxListSize);
// Perform a join between domain indicators and DNS events to identify potential malicious activity
Domain_Indicators
// Use innerunique to keep performance fast and result set low, as we only need one match to indicate potential malicious activity that needs investigation
| join kind=innerunique (
DnsEvents
| where TimeGenerated > ago(dt_lookBack)
// Extract domain patterns from syslog message
| where isnotempty(Name)
| extend parts = split(Name, '.')
| extend tld = parts[(array_length(parts)-1)]
// Validate parsed domain by checking if the TLD is in the list of TLDs in our threat feed
| where tld in~ (list_tlds)
| extend DNS_TimeGenerated = TimeGenerated
) on $left.TI_DomainEntity==$right.Name
// Filter out DNS events that occurred after the expiration of the corresponding indicator
| where DNS_TimeGenerated < ExpirationDateTime
// Group the results by IndicatorId and Name, and keep the DNS event with the latest timestamp
| summarize DNS_TimeGenerated = arg_max(DNS_TimeGenerated, *) by IndicatorId, Name
// Select the desired output fields
| project DNS_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, Url, Computer, ClientIP, Name, QueryType, Type, TI_DomainEntity
// Extract hostname and DNS domain from the Computer field
| extend HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))
// Rename the timestamp field
| extend timestamp = DNS_TimeGenerated
triggerOperator: gt
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/DomainEntity_DnsEvents.yaml
requiredDataConnectors:
- connectorId: DNS
dataTypes:
- DnsEvents
- connectorId: ThreatIntelligence
dataTypes:
- ThreatIntelligenceIndicator
- connectorId: ThreatIntelligenceTaxii
dataTypes:
- ThreatIntelligenceIndicator
- connectorId: MicrosoftDefenderThreatIntelligence
dataTypes:
- ThreatIntelligenceIndicator
tactics:
- CommandAndControl
id: 85aca4d1-5d15-4001-abd9-acb86ca1786a
queryPeriod: 14d
entityMappings:
- fieldMappings:
- columnName: Computer
identifier: FullName
- columnName: HostName
identifier: HostName
- columnName: DnsDomain
identifier: DnsDomain
entityType: Host
- fieldMappings:
- columnName: ClientIP
identifier: Address
entityType: IP
- fieldMappings:
- columnName: Url
identifier: Url
entityType: URL
{
"$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/85aca4d1-5d15-4001-abd9-acb86ca1786a')]",
"kind": "Scheduled",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/85aca4d1-5d15-4001-abd9-acb86ca1786a')]",
"properties": {
"alertRuleTemplateName": "85aca4d1-5d15-4001-abd9-acb86ca1786a",
"customDetails": null,
"description": "Identifies a match in DnsEvents from any Domain IOC from TI\n",
"displayName": "TI map Domain entity to DnsEvents",
"enabled": true,
"entityMappings": [
{
"entityType": "Host",
"fieldMappings": [
{
"columnName": "Computer",
"identifier": "FullName"
},
{
"columnName": "HostName",
"identifier": "HostName"
},
{
"columnName": "DnsDomain",
"identifier": "DnsDomain"
}
]
},
{
"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/DomainEntity_DnsEvents.yaml",
"query": "// Define the lookback periods for time-based filters\nlet dt_lookBack = 1h; // Look back 1 hour for DNS events\nlet ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators\n// Fetch threat intelligence indicators related to domains\nlet Domain_Indicators = ThreatIntelligenceIndicator\n // Filter out indicators without domain names\n | where isnotempty(DomainName)\n | where TimeGenerated >= ago(ioc_lookBack)\n | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId\n | where Active == true and ExpirationDateTime > now()\n | extend TI_DomainEntity = DomainName;\n// Create a list of TLDs in our threat feed for later validation\nlet maxListSize = 100000; // Define the maximum allowed size for each list\nlet list_tlds = Domain_Indicators\n | extend parts = split(DomainName, '.')\n | extend tld = parts[(array_length(parts)-1)]\n | summarize count() by tostring(tld)\n | project tld\n | summarize make_list(tld, maxListSize);\n// Perform a join between domain indicators and DNS events to identify potential malicious activity\nDomain_Indicators\n // Use innerunique to keep performance fast and result set low, as we only need one match to indicate potential malicious activity that needs investigation\n | join kind=innerunique (\n DnsEvents\n | where TimeGenerated > ago(dt_lookBack)\n // Extract domain patterns from syslog message\n | where isnotempty(Name)\n | extend parts = split(Name, '.')\n | extend tld = parts[(array_length(parts)-1)]\n // Validate parsed domain by checking if the TLD is in the list of TLDs in our threat feed\n | where tld in~ (list_tlds)\n | extend DNS_TimeGenerated = TimeGenerated\n ) on $left.TI_DomainEntity==$right.Name\n // Filter out DNS events that occurred after the expiration of the corresponding indicator\n | where DNS_TimeGenerated < ExpirationDateTime\n // Group the results by IndicatorId and Name, and keep the DNS event with the latest timestamp\n | summarize DNS_TimeGenerated = arg_max(DNS_TimeGenerated, *) by IndicatorId, Name\n // Select the desired output fields\n | project DNS_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, Url, Computer, ClientIP, Name, QueryType, Type, TI_DomainEntity\n // Extract hostname and DNS domain from the Computer field\n | extend HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))\n // Rename the timestamp field\n | extend timestamp = DNS_TimeGenerated\n",
"queryFrequency": "PT1H",
"queryPeriod": "P14D",
"severity": "Medium",
"subTechniques": [],
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"CommandAndControl"
],
"techniques": [
"T1071"
],
"templateVersion": "1.4.3",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0
},
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
}
]
}