Microsoft Sentinel Analytic Rules
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Cisco WSA - Unexpected file type

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Id8e9d1f70-d529-4598-9d3e-5dd5164d1d02
RulenameCisco WSA - Unexpected file type
DescriptionDetects unexpected file type.
SeverityMedium
TacticsInitialAccess
TechniquesT1189
Required data connectorsCiscoWSA
SyslogAma
KindScheduled
Query frequency1h
Query period1h
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoWSA/Analytic Rules/CiscoWSAUnexpectedFileType.yaml
Version1.0.1
Arm template8e9d1f70-d529-4598-9d3e-5dd5164d1d02.json
Deploy To Azure
CiscoWSAEvent
| where isnotempty(AmpFileName)
| where isempty(AmpThreatName)
| where ResponseBodyMimeType =~ 'application/octet-stream'
| where AmpFileName !endswith '.exe'
| extend IPCustomEntity = SrcIpAddr, AccountCustomEntity = SrcUserName
relevantTechniques:
- T1189
name: Cisco WSA - Unexpected file type
requiredDataConnectors:
- dataTypes:
  - CiscoWSAEvent
  connectorId: CiscoWSA
- datatypes:
  - Syslog
  connectorId: SyslogAma
entityMappings:
- fieldMappings:
  - identifier: Address
    columnName: IPCustomEntity
  entityType: IP
- fieldMappings:
  - identifier: Name
    columnName: AccountCustomEntity
  entityType: Account
triggerThreshold: 0
id: 8e9d1f70-d529-4598-9d3e-5dd5164d1d02
tactics:
- InitialAccess
version: 1.0.1
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoWSA/Analytic Rules/CiscoWSAUnexpectedFileType.yaml
queryPeriod: 1h
kind: Scheduled
queryFrequency: 1h
severity: Medium
status: Available
description: |
    'Detects unexpected file type.'
query: |
  CiscoWSAEvent
  | where isnotempty(AmpFileName)
  | where isempty(AmpThreatName)
  | where ResponseBodyMimeType =~ 'application/octet-stream'
  | where AmpFileName !endswith '.exe'
  | extend IPCustomEntity = SrcIpAddr, AccountCustomEntity = SrcUserName  
triggerOperator: gt
{
  "$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/8e9d1f70-d529-4598-9d3e-5dd5164d1d02')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/8e9d1f70-d529-4598-9d3e-5dd5164d1d02')]",
      "properties": {
        "alertRuleTemplateName": "8e9d1f70-d529-4598-9d3e-5dd5164d1d02",
        "customDetails": null,
        "description": "'Detects unexpected file type.'\n",
        "displayName": "Cisco WSA - Unexpected file type",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "IPCustomEntity",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "AccountCustomEntity",
                "identifier": "Name"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoWSA/Analytic Rules/CiscoWSAUnexpectedFileType.yaml",
        "query": "CiscoWSAEvent\n| where isnotempty(AmpFileName)\n| where isempty(AmpThreatName)\n| where ResponseBodyMimeType =~ 'application/octet-stream'\n| where AmpFileName !endswith '.exe'\n| extend IPCustomEntity = SrcIpAddr, AccountCustomEntity = SrcUserName\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "techniques": [
          "T1189"
        ],
        "templateVersion": "1.0.1",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}