Cisco ASA - Possible Data Exfiltration Detection

let Lookback = 1h;
let MinUploadBytes = 1073741824;
let MinUploadRatio = 95.0;
CommonSecurityLog
| where TimeGenerated > ago(Lookback)
| where DeviceProduct has_any ("ASA", "FTD")
| where isnotempty(SourceIP) and isnotempty(DestinationIP)
| where ipv4_is_private(SourceIP)
| where not(ipv4_is_private(DestinationIP))
| where DeviceAction in~ ("allow", "allowed", "accept", "accepted", "permitted")
| extend SentBytesLong = tolong(SentBytes)
| extend ReceivedBytesLong = tolong(ReceivedBytes)
| where isnotnull(SentBytesLong)
| summarize
    TotalBytesSent = sum(SentBytesLong),
    TotalBytesReceived = sum(coalesce(ReceivedBytesLong, 0)),
    Connections = count(),
    DestinationPorts = make_set(DestinationPort, 20),
    Applications = make_set(ApplicationProtocol, 20),
    FirstSeen = min(TimeGenerated),
    LastSeen = max(TimeGenerated)
    by SourceIP, DestinationIP
| where TotalBytesSent >= MinUploadBytes
| extend TotalGBSent = round(TotalBytesSent / 1024.0 / 1024.0 / 1024.0, 2)
| extend TotalGBReceived = round(TotalBytesReceived / 1024.0 / 1024.0 / 1024.0, 2)
| extend UploadRatio = round(todouble(TotalBytesSent) / todouble(TotalBytesSent + TotalBytesReceived) * 100, 2)
| where UploadRatio >= MinUploadRatio
| project
    TimeGenerated = LastSeen,
    SourceIP,
    DestinationIP,
    TotalGBSent,
    TotalGBReceived,
    UploadRatio,
    Connections,
    DestinationPorts,
    Applications,
    FirstSeen,
    LastSeen
| order by TotalGBSent desc

name: Cisco ASA - Possible Data Exfiltration Detection
triggerOperator: gt
query: |
  let Lookback = 1h;
  let MinUploadBytes = 1073741824;
  let MinUploadRatio = 95.0;
  CommonSecurityLog
  | where TimeGenerated > ago(Lookback)
  | where DeviceProduct has_any ("ASA", "FTD")
  | where isnotempty(SourceIP) and isnotempty(DestinationIP)
  | where ipv4_is_private(SourceIP)
  | where not(ipv4_is_private(DestinationIP))
  | where DeviceAction in~ ("allow", "allowed", "accept", "accepted", "permitted")
  | extend SentBytesLong = tolong(SentBytes)
  | extend ReceivedBytesLong = tolong(ReceivedBytes)
  | where isnotnull(SentBytesLong)
  | summarize
      TotalBytesSent = sum(SentBytesLong),
      TotalBytesReceived = sum(coalesce(ReceivedBytesLong, 0)),
      Connections = count(),
      DestinationPorts = make_set(DestinationPort, 20),
      Applications = make_set(ApplicationProtocol, 20),
      FirstSeen = min(TimeGenerated),
      LastSeen = max(TimeGenerated)
      by SourceIP, DestinationIP
  | where TotalBytesSent >= MinUploadBytes
  | extend TotalGBSent = round(TotalBytesSent / 1024.0 / 1024.0 / 1024.0, 2)
  | extend TotalGBReceived = round(TotalBytesReceived / 1024.0 / 1024.0 / 1024.0, 2)
  | extend UploadRatio = round(todouble(TotalBytesSent) / todouble(TotalBytesSent + TotalBytesReceived) * 100, 2)
  | where UploadRatio >= MinUploadRatio
  | project
      TimeGenerated = LastSeen,
      SourceIP,
      DestinationIP,
      TotalGBSent,
      TotalGBReceived,
      UploadRatio,
      Connections,
      DestinationPorts,
      Applications,
      FirstSeen,
      LastSeen
  | order by TotalGBSent desc
queryFrequency: 1h
description: |
  'Detects potential data exfiltration when an internal source IP sends a large amount of outbound data to the internet, especially when the volume is significantly higher than its normal behavior.'
id: f3a8c2d0-7b41-4e9a-9f6a-2d8a1c4e5b72
triggerThreshold: 0
queryPeriod: 1h
version: 1.0.2
kind: Scheduled
status: Available
severity: Medium
requiredDataConnectors:
- connectorId: CiscoAsaAma
  dataTypes:
  - CommonSecurityLog
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoASA/Analytic%20Rules/CiscoASA-PossibleDataExfiltration.yaml
relevantTechniques:
- T1041
- T1048
tactics:
- Exfiltration
entityMappings:
- fieldMappings:
  - identifier: Address
    columnName: SourceIP
  entityType: IP
- fieldMappings:
  - identifier: Address
    columnName: DestinationIP
  entityType: IP

{
  "$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/f3a8c2d0-7b41-4e9a-9f6a-2d8a1c4e5b72')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/f3a8c2d0-7b41-4e9a-9f6a-2d8a1c4e5b72')]",
      "properties": {
        "alertRuleTemplateName": "f3a8c2d0-7b41-4e9a-9f6a-2d8a1c4e5b72",
        "customDetails": null,
        "description": "'Detects potential data exfiltration when an internal source IP sends a large amount of outbound data to the internet, especially when the volume is significantly higher than its normal behavior.'\n",
        "displayName": "Cisco ASA - Possible Data Exfiltration Detection",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SourceIP",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "DestinationIP",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoASA/Analytic%20Rules/CiscoASA-PossibleDataExfiltration.yaml",
        "query": "let Lookback = 1h;\nlet MinUploadBytes = 1073741824;\nlet MinUploadRatio = 95.0;\nCommonSecurityLog\n| where TimeGenerated > ago(Lookback)\n| where DeviceProduct has_any (\"ASA\", \"FTD\")\n| where isnotempty(SourceIP) and isnotempty(DestinationIP)\n| where ipv4_is_private(SourceIP)\n| where not(ipv4_is_private(DestinationIP))\n| where DeviceAction in~ (\"allow\", \"allowed\", \"accept\", \"accepted\", \"permitted\")\n| extend SentBytesLong = tolong(SentBytes)\n| extend ReceivedBytesLong = tolong(ReceivedBytes)\n| where isnotnull(SentBytesLong)\n| summarize\n    TotalBytesSent = sum(SentBytesLong),\n    TotalBytesReceived = sum(coalesce(ReceivedBytesLong, 0)),\n    Connections = count(),\n    DestinationPorts = make_set(DestinationPort, 20),\n    Applications = make_set(ApplicationProtocol, 20),\n    FirstSeen = min(TimeGenerated),\n    LastSeen = max(TimeGenerated)\n    by SourceIP, DestinationIP\n| where TotalBytesSent >= MinUploadBytes\n| extend TotalGBSent = round(TotalBytesSent / 1024.0 / 1024.0 / 1024.0, 2)\n| extend TotalGBReceived = round(TotalBytesReceived / 1024.0 / 1024.0 / 1024.0, 2)\n| extend UploadRatio = round(todouble(TotalBytesSent) / todouble(TotalBytesSent + TotalBytesReceived) * 100, 2)\n| where UploadRatio >= MinUploadRatio\n| project\n    TimeGenerated = LastSeen,\n    SourceIP,\n    DestinationIP,\n    TotalGBSent,\n    TotalGBReceived,\n    UploadRatio,\n    Connections,\n    DestinationPorts,\n    Applications,\n    FirstSeen,\n    LastSeen\n| order by TotalGBSent desc\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Exfiltration"
        ],
        "techniques": [
          "T1041",
          "T1048"
        ],
        "templateVersion": "1.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}