TI map Domain entity to Web Session Events (ASIM Web Session schema)
Id | b1832f60-6c3d-4722-a0a5-3d564ee61a63 |
Rulename | TI map Domain entity to Web Session Events (ASIM Web Session schema) |
Description | This rule identifies Web Sessions for which the target URL hostname is a known IoC. <br><br>This rule uses the Advanced Security Information Model (ASIM) and supports any web session source that complies with ASIM. |
Severity | Medium |
Tactics | Impact |
Required data connectors | MicrosoftDefenderThreatIntelligence SquidProxy ThreatIntelligence Zscaler |
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_imWebSession.yaml |
Version | 1.0.4 |
Arm template | b1832f60-6c3d-4722-a0a5-3d564ee61a63.json |
let HAS_ANY_MAX = 10000;
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
//Create a list of TLDs in our threat feed for later validation
let DOMAIN_TI=ThreatIntelligenceIndicator
| where TimeGenerated >= ago(ioc_lookBack) and ExpirationDateTime > now()
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true
// Picking up only IOC's that contain the entities we want
| where isnotempty(DomainName);
let DOMAIN_TI_list= todynamic(toscalar(DOMAIN_TI | summarize NIoCs = dcount(DomainName), Domains = make_set(DomainName)
| project Domains=iff(NIoCs > HAS_ANY_MAX, dynamic([]), Domains) ));
DOMAIN_TI
// 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 (
_Im_WebSession(starttime=ago(dt_lookBack), url_has_any= DOMAIN_TI_list )
//Extract domain patterns from syslog message
| extend domain = tostring(parse_url(Url)["Host"])
| where isnotempty(domain)
| extend tld = tostring(split(domain, '.')[-1])
| extend Event_TimeGenerated = TimeGenerated
) on $left.DomainName==$right.domain
| where Event_TimeGenerated < ExpirationDateTime
| summarize Event_TimeGenerated = arg_max(Event_TimeGenerated , *) by IndicatorId, domain
| project Event_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, domain, SrcIpAddr, Url
kind: Scheduled
triggerOperator: gt
queryFrequency: 1h
name: TI map Domain entity to Web Session Events (ASIM Web Session schema)
alertDetailsOverride:
alertDescriptionFormat: A client with address {{SrcIpAddr}} requested the URL {{Url}}, whose hostname is a known indicator of compromise of {{ThreatType}}. Consult the threat intelligence blade for more information on the indicator.
alertDisplayNameFormat: A web request from {{SrcIpAddr}} to hostname {{domain}} matched an IoC
queryPeriod: 14d
id: b1832f60-6c3d-4722-a0a5-3d564ee61a63
description: |
'This rule identifies Web Sessions for which the target URL hostname is a known IoC. <br><br>This rule uses the [Advanced Security Information Model (ASIM)](https:/aka.ms/AboutASIM) and supports any web session source that complies with ASIM.'
severity: Medium
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/DomainEntity_imWebSession.yaml
query: |
let HAS_ANY_MAX = 10000;
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
//Create a list of TLDs in our threat feed for later validation
let DOMAIN_TI=ThreatIntelligenceIndicator
| where TimeGenerated >= ago(ioc_lookBack) and ExpirationDateTime > now()
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true
// Picking up only IOC's that contain the entities we want
| where isnotempty(DomainName);
let DOMAIN_TI_list= todynamic(toscalar(DOMAIN_TI | summarize NIoCs = dcount(DomainName), Domains = make_set(DomainName)
| project Domains=iff(NIoCs > HAS_ANY_MAX, dynamic([]), Domains) ));
DOMAIN_TI
// 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 (
_Im_WebSession(starttime=ago(dt_lookBack), url_has_any= DOMAIN_TI_list )
//Extract domain patterns from syslog message
| extend domain = tostring(parse_url(Url)["Host"])
| where isnotempty(domain)
| extend tld = tostring(split(domain, '.')[-1])
| extend Event_TimeGenerated = TimeGenerated
) on $left.DomainName==$right.domain
| where Event_TimeGenerated < ExpirationDateTime
| summarize Event_TimeGenerated = arg_max(Event_TimeGenerated , *) by IndicatorId, domain
| project Event_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, domain, SrcIpAddr, Url
version: 1.0.4
customDetails:
IoCDescription: Description
IoCConfidenceScore: ConfidenceScore
ThreatType: ThreatType
IoCExpirationTime: ExpirationDateTime
ActivityGroupNames: ActivityGroupNames
IndicatorId: IndicatorId
EventTime: Event_TimeGenerated
entityMappings:
- entityType: IP
fieldMappings:
- identifier: Address
columnName: SrcIpAddr
- entityType: URL
fieldMappings:
- identifier: Url
columnName: Url
requiredDataConnectors:
- connectorId: SquidProxy
dataTypes:
- SquidProxy_CL
- connectorId: Zscaler
dataTypes:
- CommonSecurityLog
- connectorId: ThreatIntelligence
dataTypes:
- ThreatIntelligenceIndicator
- connectorId: MicrosoftDefenderThreatIntelligence
dataTypes:
- ThreatIntelligenceIndicator
tactics:
- Impact
triggerThreshold: 0
{
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"workspace": {
"type": "String"
}
},
"resources": [
{
"id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/b1832f60-6c3d-4722-a0a5-3d564ee61a63')]",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/b1832f60-6c3d-4722-a0a5-3d564ee61a63')]",
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
"kind": "Scheduled",
"apiVersion": "2022-11-01-preview",
"properties": {
"displayName": "TI map Domain entity to Web Session Events (ASIM Web Session schema)",
"description": "'This rule identifies Web Sessions for which the target URL hostname is a known IoC. <br><br>This rule uses the [Advanced Security Information Model (ASIM)](https:/aka.ms/AboutASIM) and supports any web session source that complies with ASIM.'\n",
"severity": "Medium",
"enabled": true,
"query": "let HAS_ANY_MAX = 10000;\nlet dt_lookBack = 1h;\nlet ioc_lookBack = 14d;\n//Create a list of TLDs in our threat feed for later validation\nlet DOMAIN_TI=ThreatIntelligenceIndicator\n| where TimeGenerated >= ago(ioc_lookBack) and ExpirationDateTime > now()\n| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId\n| where Active == true\n// Picking up only IOC's that contain the entities we want\n| where isnotempty(DomainName);\nlet DOMAIN_TI_list= todynamic(toscalar(DOMAIN_TI | summarize NIoCs = dcount(DomainName), Domains = make_set(DomainName) \n | project Domains=iff(NIoCs > HAS_ANY_MAX, dynamic([]), Domains) ));\nDOMAIN_TI\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 (\n _Im_WebSession(starttime=ago(dt_lookBack), url_has_any= DOMAIN_TI_list )\n //Extract domain patterns from syslog message\n | extend domain = tostring(parse_url(Url)[\"Host\"])\n | where isnotempty(domain)\n | extend tld = tostring(split(domain, '.')[-1])\n | extend Event_TimeGenerated = TimeGenerated\n) on $left.DomainName==$right.domain\n| where Event_TimeGenerated < ExpirationDateTime\n| summarize Event_TimeGenerated = arg_max(Event_TimeGenerated , *) by IndicatorId, domain\n| project Event_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, domain, SrcIpAddr, Url \n",
"queryFrequency": "PT1H",
"queryPeriod": "P14D",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0,
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"Impact"
],
"alertRuleTemplateName": "b1832f60-6c3d-4722-a0a5-3d564ee61a63",
"alertDetailsOverride": {
"alertDisplayNameFormat": "A web request from {{SrcIpAddr}} to hostname {{domain}} matched an IoC",
"alertDescriptionFormat": "A client with address {{SrcIpAddr}} requested the URL {{Url}}, whose hostname is a known indicator of compromise of {{ThreatType}}. Consult the threat intelligence blade for more information on the indicator."
},
"customDetails": {
"IoCDescription": "Description",
"IndicatorId": "IndicatorId",
"IoCConfidenceScore": "ConfidenceScore",
"ThreatType": "ThreatType",
"ActivityGroupNames": "ActivityGroupNames",
"IoCExpirationTime": "ExpirationDateTime",
"EventTime": "Event_TimeGenerated"
},
"entityMappings": [
{
"fieldMappings": [
{
"identifier": "Address",
"columnName": "SrcIpAddr"
}
],
"entityType": "IP"
},
{
"fieldMappings": [
{
"identifier": "Url",
"columnName": "Url"
}
],
"entityType": "URL"
}
],
"OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/DomainEntity_imWebSession.yaml",
"templateVersion": "1.0.4"
}
}
]
}