let e_theshold = 3;
let s_threshold = 10000000;
CiscoSEGEvent
| where AdditionalFields[15]['ESAMsgSize'] > s_threshold
| where NetworkDirection =~ 'Outgoing'
| extend rec_domain = extract(@'@(.*)', 1, DstUserName)
| extend s_domain = extract(@'@(.*)', 1, SrcUserName)
| where s_domain != rec_domain
| summarize count() by SrcUserName
| where count_ >= e_theshold
| extend AccountCustomEntity = SrcUserName
queryPeriod: 1h
version: 1.0.0
relevantTechniques:
- T1030
queryFrequency: 1h
kind: Scheduled
name: Cisco SEG - Multiple large emails sent to external recipient
id: 1399a9a5-6200-411e-8c34-ca5658754cf7
entityMappings:
- fieldMappings:
- columnName: AccountCustomEntity
identifier: Name
entityType: Account
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoSEG/Analytic Rules/CiscoSEGMultipleLargeEmails.yaml
severity: Medium
query: |
let e_theshold = 3;
let s_threshold = 10000000;
CiscoSEGEvent
| where AdditionalFields[15]['ESAMsgSize'] > s_threshold
| where NetworkDirection =~ 'Outgoing'
| extend rec_domain = extract(@'@(.*)', 1, DstUserName)
| extend s_domain = extract(@'@(.*)', 1, SrcUserName)
| where s_domain != rec_domain
| summarize count() by SrcUserName
| where count_ >= e_theshold
| extend AccountCustomEntity = SrcUserName
tactics:
- Exfiltration
description: |
'Detects possible data exfiltration.'
requiredDataConnectors:
- connectorId: CiscoSEG
dataTypes:
- CiscoSEGEvent
status: Available
triggerThreshold: 0
triggerOperator: gt
{
"$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/1399a9a5-6200-411e-8c34-ca5658754cf7')]",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/1399a9a5-6200-411e-8c34-ca5658754cf7')]",
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
"kind": "Scheduled",
"apiVersion": "2022-11-01",
"properties": {
"displayName": "Cisco SEG - Multiple large emails sent to external recipient",
"description": "'Detects possible data exfiltration.'\n",
"severity": "Medium",
"enabled": true,
"query": "let e_theshold = 3;\nlet s_threshold = 10000000;\nCiscoSEGEvent\n| where AdditionalFields[15]['ESAMsgSize'] > s_threshold\n| where NetworkDirection =~ 'Outgoing'\n| extend rec_domain = extract(@'@(.*)', 1, DstUserName)\n| extend s_domain = extract(@'@(.*)', 1, SrcUserName)\n| where s_domain != rec_domain\n| summarize count() by SrcUserName\n| where count_ >= e_theshold\n| extend AccountCustomEntity = SrcUserName\n",
"queryFrequency": "PT1H",
"queryPeriod": "PT1H",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0,
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"Exfiltration"
],
"techniques": [
"T1030"
],
"alertRuleTemplateName": "1399a9a5-6200-411e-8c34-ca5658754cf7",
"customDetails": null,
"entityMappings": [
{
"fieldMappings": [
{
"identifier": "Name",
"columnName": "AccountCustomEntity"
}
],
"entityType": "Account"
}
],
"OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoSEG/Analytic Rules/CiscoSEGMultipleLargeEmails.yaml",
"status": "Available",
"templateVersion": "1.0.0"
}
}
]
}