PRODAFT USTA - TI map File Hash to CommonSecurityLog

let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let fileHashIndicators = ThreatIntelIndicators
// Each USTA IoC feed uploads under its own SourceSystem ("PRODAFT USTA - Malware Hashes", etc.)
| where SourceSystem startswith "PRODAFT USTA"
// ObservableKey is a STIX kv pair ("file:hashes.'SHA-256'") - take the type before the colon
| extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
| where IndicatorType == "file"
| extend FileHashType = extract(@"hashes\.'([^']+)'", 1, ObservableKey)
| where isnotempty(FileHashType)
| extend FileHashValue = toupper(ObservableValue)
| extend IndicatorId = tostring(split(Id, "--")[2])
| extend Url = iff(ObservableKey == "url:value", ObservableValue, "")
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
| where IsActive and (ValidUntil > now() or isempty(ValidUntil));
// CommonSecurityLog hash casing varies by source, so match both forms
(fileHashIndicators | extend  FileHashValue = tolower(FileHashValue)
| union (fileHashIndicators | extend FileHashValue = toupper(FileHashValue)))
| project-reorder *, FileHashType, FileHashValue, Type
// innerunique: one match per indicator is enough to alert, and it keeps the join cheap
|  join kind=innerunique (
  CommonSecurityLog | where TimeGenerated >= ago(dt_lookBack)
  | extend CommonSecurityLog_TimeGenerated = TimeGenerated
  )
on $left.FileHashValue == $right.FileHash
// non-expiring indicators are allowed above, so they must survive this filter too
| where isempty(ValidUntil) or CommonSecurityLog_TimeGenerated < ValidUntil
| summarize CommonSecurityLog_TimeGenerated = arg_max(CommonSecurityLog_TimeGenerated, *) by IndicatorId, FileHashValue
| extend Description = tostring(parse_json(Data).description)
| extend IndicatorTags = tostring(parse_json(Data).labels)
| project CommonSecurityLog_TimeGenerated, Description, IndicatorTags, Id, ValidUntil, Confidence,
SourceIP, SourcePort, DestinationIP, DestinationPort, SourceUserID, SourceUserName, DeviceName, DeviceAction,
RequestURL, DestinationUserName, DestinationUserID, ApplicationProtocol, Activity, FileHashValue, FileHashType, Url
| extend HostName = tostring(split(DeviceName, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(DeviceName, '.'), 1, -1), '.'))
| extend Name = tostring(split(SourceUserName, '@', 0)[0]), UPNSuffix = tostring(split(SourceUserName, '@', 1)[0])
| extend timestamp = CommonSecurityLog_TimeGenerated

name: PRODAFT USTA - TI map File Hash to CommonSecurityLog
triggerOperator: gt
query: |
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let fileHashIndicators = ThreatIntelIndicators
  // Each USTA IoC feed uploads under its own SourceSystem ("PRODAFT USTA - Malware Hashes", etc.)
  | where SourceSystem startswith "PRODAFT USTA"
  // ObservableKey is a STIX kv pair ("file:hashes.'SHA-256'") - take the type before the colon
  | extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
  | where IndicatorType == "file"
  | extend FileHashType = extract(@"hashes\.'([^']+)'", 1, ObservableKey)
  | where isnotempty(FileHashType)
  | extend FileHashValue = toupper(ObservableValue)
  | extend IndicatorId = tostring(split(Id, "--")[2])
  | extend Url = iff(ObservableKey == "url:value", ObservableValue, "")
  | where TimeGenerated >= ago(ioc_lookBack)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
  | where IsActive and (ValidUntil > now() or isempty(ValidUntil));
  // CommonSecurityLog hash casing varies by source, so match both forms
  (fileHashIndicators | extend  FileHashValue = tolower(FileHashValue)
  | union (fileHashIndicators | extend FileHashValue = toupper(FileHashValue)))
  | project-reorder *, FileHashType, FileHashValue, Type
  // innerunique: one match per indicator is enough to alert, and it keeps the join cheap
  |  join kind=innerunique (
    CommonSecurityLog | where TimeGenerated >= ago(dt_lookBack)
    | extend CommonSecurityLog_TimeGenerated = TimeGenerated
    )
  on $left.FileHashValue == $right.FileHash
  // non-expiring indicators are allowed above, so they must survive this filter too
  | where isempty(ValidUntil) or CommonSecurityLog_TimeGenerated < ValidUntil
  | summarize CommonSecurityLog_TimeGenerated = arg_max(CommonSecurityLog_TimeGenerated, *) by IndicatorId, FileHashValue
  | extend Description = tostring(parse_json(Data).description)
  | extend IndicatorTags = tostring(parse_json(Data).labels)
  | project CommonSecurityLog_TimeGenerated, Description, IndicatorTags, Id, ValidUntil, Confidence,
  SourceIP, SourcePort, DestinationIP, DestinationPort, SourceUserID, SourceUserName, DeviceName, DeviceAction,
  RequestURL, DestinationUserName, DestinationUserID, ApplicationProtocol, Activity, FileHashValue, FileHashType, Url
  | extend HostName = tostring(split(DeviceName, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(DeviceName, '.'), 1, -1), '.'))
  | extend Name = tostring(split(SourceUserName, '@', 0)[0]), UPNSuffix = tostring(split(SourceUserName, '@', 1)[0])
  | extend timestamp = CommonSecurityLog_TimeGenerated
queryFrequency: 1h
description: |
  'Identifies a match in CommonSecurityLog data from any file-hash indicator ingested from
  PRODAFT USTA IoC Threat Intelligence (SourceSystem starting with "PRODAFT USTA").'
id: 9c2cef4e-c3a3-4be9-8923-a2f820d4face
triggerThreshold: 0
queryPeriod: 14d
version: 1.0.0
kind: Scheduled
relevantTechniques:
- T1071
severity: Medium
requiredDataConnectors:
- connectorId: CefAma
  dataTypes:
  - CommonSecurityLog
- connectorId: PRODAFTUstaIoCUploadIndicators
  dataTypes:
  - ThreatIntelIndicators
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/PRODAFT%20USTA%20-%20IoC%20Threat%20Intelligence/Analytic%20Rules/TIMapFileHashToCommonSecurityLog.yaml
tactics:
- CommandAndControl
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: SourceUserName
  - identifier: Name
    columnName: Name
  - identifier: UPNSuffix
    columnName: UPNSuffix
  entityType: Account
- fieldMappings:
  - identifier: FullName
    columnName: DeviceName
  - identifier: HostName
    columnName: HostName
  - identifier: DnsDomain
    columnName: DnsDomain
  entityType: Host
- fieldMappings:
  - identifier: Address
    columnName: SourceIP
  entityType: IP
- fieldMappings:
  - identifier: Url
    columnName: Url
  entityType: URL
- fieldMappings:
  - identifier: Value
    columnName: FileHashValue
  - identifier: Algorithm
    columnName: FileHashType
  entityType: FileHash

{
  "$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/9c2cef4e-c3a3-4be9-8923-a2f820d4face')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/9c2cef4e-c3a3-4be9-8923-a2f820d4face')]",
      "properties": {
        "alertRuleTemplateName": "9c2cef4e-c3a3-4be9-8923-a2f820d4face",
        "customDetails": null,
        "description": "'Identifies a match in CommonSecurityLog data from any file-hash indicator ingested from\nPRODAFT USTA IoC Threat Intelligence (SourceSystem starting with \"PRODAFT USTA\").'\n",
        "displayName": "PRODAFT USTA - TI map File Hash to CommonSecurityLog",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "SourceUserName",
                "identifier": "FullName"
              },
              {
                "columnName": "Name",
                "identifier": "Name"
              },
              {
                "columnName": "UPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "DeviceName",
                "identifier": "FullName"
              },
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "DnsDomain",
                "identifier": "DnsDomain"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SourceIP",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "URL",
            "fieldMappings": [
              {
                "columnName": "Url",
                "identifier": "Url"
              }
            ]
          },
          {
            "entityType": "FileHash",
            "fieldMappings": [
              {
                "columnName": "FileHashValue",
                "identifier": "Value"
              },
              {
                "columnName": "FileHashType",
                "identifier": "Algorithm"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/PRODAFT%20USTA%20-%20IoC%20Threat%20Intelligence/Analytic%20Rules/TIMapFileHashToCommonSecurityLog.yaml",
        "query": "let dt_lookBack = 1h;\nlet ioc_lookBack = 14d;\nlet fileHashIndicators = ThreatIntelIndicators\n// Each USTA IoC feed uploads under its own SourceSystem (\"PRODAFT USTA - Malware Hashes\", etc.)\n| where SourceSystem startswith \"PRODAFT USTA\"\n// ObservableKey is a STIX kv pair (\"file:hashes.'SHA-256'\") - take the type before the colon\n| extend IndicatorType = replace(@\"\\[|\\]|\\\"\"\", \"\", tostring(split(ObservableKey, \":\", 0)))\n| where IndicatorType == \"file\"\n| extend FileHashType = extract(@\"hashes\\.'([^']+)'\", 1, ObservableKey)\n| where isnotempty(FileHashType)\n| extend FileHashValue = toupper(ObservableValue)\n| extend IndicatorId = tostring(split(Id, \"--\")[2])\n| extend Url = iff(ObservableKey == \"url:value\", ObservableValue, \"\")\n| where TimeGenerated >= ago(ioc_lookBack)\n| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue\n| where IsActive and (ValidUntil > now() or isempty(ValidUntil));\n// CommonSecurityLog hash casing varies by source, so match both forms\n(fileHashIndicators | extend  FileHashValue = tolower(FileHashValue)\n| union (fileHashIndicators | extend FileHashValue = toupper(FileHashValue)))\n| project-reorder *, FileHashType, FileHashValue, Type\n// innerunique: one match per indicator is enough to alert, and it keeps the join cheap\n|  join kind=innerunique (\n  CommonSecurityLog | where TimeGenerated >= ago(dt_lookBack)\n  | extend CommonSecurityLog_TimeGenerated = TimeGenerated\n  )\non $left.FileHashValue == $right.FileHash\n// non-expiring indicators are allowed above, so they must survive this filter too\n| where isempty(ValidUntil) or CommonSecurityLog_TimeGenerated < ValidUntil\n| summarize CommonSecurityLog_TimeGenerated = arg_max(CommonSecurityLog_TimeGenerated, *) by IndicatorId, FileHashValue\n| extend Description = tostring(parse_json(Data).description)\n| extend IndicatorTags = tostring(parse_json(Data).labels)\n| project CommonSecurityLog_TimeGenerated, Description, IndicatorTags, Id, ValidUntil, Confidence,\nSourceIP, SourcePort, DestinationIP, DestinationPort, SourceUserID, SourceUserName, DeviceName, DeviceAction,\nRequestURL, DestinationUserName, DestinationUserID, ApplicationProtocol, Activity, FileHashValue, FileHashType, Url\n| extend HostName = tostring(split(DeviceName, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(DeviceName, '.'), 1, -1), '.'))\n| extend Name = tostring(split(SourceUserName, '@', 0)[0]), UPNSuffix = tostring(split(SourceUserName, '@', 1)[0])\n| extend timestamp = CommonSecurityLog_TimeGenerated\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl"
        ],
        "techniques": [
          "T1071"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}